Artificial joint components including synovial fluid deflecting structures and particle retaining structures

ABSTRACT

Artificial joint prostheses, including hip, knee and shoulder joints, are described. In some aspects, an artificial joint prosthesis includes: a bone-facing surface of an artificial joint prosthesis, the bone-facing surface configured to face a bone-prosthesis interface in vivo; a non-contact surface of the artificial joint prosthesis, the non-contact surface adjacent to the bone-facing surface of the artificial joint prosthesis; at least one fluid deflection structure attached to the non-contact surface, the fluid deflection structure positioned to direct a flow of synovial fluid away from the bone-prosthesis interface in vivo; and at least one particle retaining structure positioned to contact the directed flow of synovial fluid and configured to retain particles present within the synovial fluid.

If an Application Data Sheet (ADS) has been filed on the filing date ofthis application, it is incorporated by reference herein. Anyapplications claimed on the ADS for priority under 35 U.S.C. §§119, 120,121, or 365(c), and any and all parent, grandparent, great-grandparent,etc. applications of such applications, are also incorporated byreference, including any priority claims made in those applications andany material incorporated by reference, to the extent such subjectmatter is not inconsistent herewith.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to and/or claims the benefit of theearliest available effective filing date(s) from the following listedapplication(s) (the “Priority Applications”), if any, listed below(e.g., claims earliest available priority dates for other thanprovisional patent applications or claims benefits under 35 USC §119(e)for provisional patent applications, for any and all parent,grandparent, great-grandparent, etc. applications of the PriorityApplication(s)). In addition, the present application is related to the“Related Applications,” if any, listed below.

PRIORITY APPLICATIONS

For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation-in-part of U.S. patentapplication Ser. No. 13/628,442, entitled ARTIFICIAL JOINT COMPONENTSINCLUDING SYNOVIAL FLUID DEFLECTING STRUCTURES, naming Edward S. Boyden;Gregory J. Della Rocca; Daniel Hawkins; Roderick A. Hyde; Robert Langer;Eric C. Leuthardt; Terence Myckatyn; Parag Jitendra Parikh; Dennis J.Rivet; Joshua S. Shimony; Michael A. Smith; and Clarence T. Tegreene asinventors, filed 27 Sep. 2012, which is currently co-pending.

RELATED APPLICATIONS

None.

The United States Patent Office (USPTO) has published a notice to theeffect that the USPTO's computer programs require that patent applicantsreference both a serial number and indicate whether an application is acontinuation, continuation-in-part, or divisional of a parentapplication. Stephen G. Kunin, Benefit of Prior-Filed Application, USPTOOfficial Gazette Mar. 18, 2003. The USPTO further has provided forms forthe Application Data Sheet which allow automatic loading ofbibliographic data but which require identification of each applicationas a continuation, continuation-in-part, or divisional of a parentapplication. The present Applicant Entity (hereinafter “Applicant”) hasprovided above a specific reference to the application(s) from whichpriority is being claimed as recited by statute. Applicant understandsthat the statute is unambiguous in its specific reference language anddoes not require either a serial number or any characterization, such as“continuation” or “continuation-in-part,” for claiming priority to U.S.patent applications. Notwithstanding the foregoing, Applicantunderstands that the USPTO's computer programs have certain data entryrequirements, and hence Applicant has provided designation(s) of arelationship between the present application and its parentapplication(s) as set forth above and in any ADS filed in thisapplication, but expressly points out that such designation(s) are notto be construed in any way as any type of commentary and/or admission asto whether or not the present application contains any new matter inaddition to the matter of its parent application(s).

If the listings of applications provided above are inconsistent with thelistings provided via an ADS, it is the intent of the Applicant to claimpriority to each application that appears in the Priority Applicationssection of the ADS and to each application that appears in the PriorityApplications section of this application.

All subject matter of the Priority Applications and the RelatedApplications and of any and all parent, grandparent, great-grandparent,etc. applications of the Priority Applications and the RelatedApplications, including any priority claims, is incorporated herein byreference to the extent such subject matter is not inconsistentherewith.

SUMMARY

In one aspect, an artificial joint prosthesis includes: a bone-facingsurface of a artificial joint prosthesis, the bone-facing surfaceconfigured to face a bone-prosthesis interface in vivo; a non-loadbearing surface of the artificial joint prosthesis, the non-load bearingsurface adjacent to the bone-facing surface of the artificial jointprosthesis; at least one fluid deflection structure attached to thenon-load bearing surface, the fluid deflection structure positioned todirect a flow of synovial fluid away from the bone-prosthesis interfacein vivo during physiological movement of the artificial jointprosthesis; and at least one particle retaining structure positioned tocontact the directed flow of synovial fluid and configured to retainnon-physiological particles present within the synovial fluid. In oneaspect, an artificial joint prosthesis includes: a bone-facing surfaceof a artificial joint prosthesis, the bone-facing surface configured toface a bone-prosthesis interface in vivo; a non-load bearing surface ofthe artificial joint prosthesis, the non-load bearing surface adjacentto the bone-facing surface of the artificial joint prosthesis; at leastone fluid deflection structure attached to the non-load bearing surface,the fluid deflection structure positioned to direct a flow of synovialfluid away from the bone-prosthesis interface in vivo duringphysiological movement of the artificial joint prosthesis; and at leastone particle retaining structure positioned to contact the directed flowof synovial fluid and configured to retain non-physiological particlespresent within the synovial fluid.

In some aspects, a hip joint prosthesis includes: a bone-facing surfaceof a hip joint prosthesis, the bone-facing surface configured to face abone-prosthesis interface in vivo; a non-contact surface of the hipjoint prosthesis, the non-contact surface adjacent to the bone-facingsurface of the hip joint prosthesis; at least one fluid deflectionstructure attached to the non-contact surface, the fluid deflectionstructure positioned to direct a flow of synovial fluid away from thebone-prosthesis interface in vivo; and at least one particle retainingstructure positioned to contact the directed flow of synovial fluid andconfigured to retain particles present within the synovial fluid.

In some aspects, a knee joint prosthesis includes: a bone-facing surfaceof a knee joint prosthesis, the bone-facing surface configured to face abone-prosthesis interface in vivo; a non-contact surface of the kneejoint prosthesis, the non-contact surface adjacent to the bone-facingsurface of the knee joint prosthesis; at least one fluid deflectionstructure attached to the non-contact surface, the fluid deflectionstructure positioned to direct a flow of synovial fluid away from thebone-prosthesis interface in vivo; and at least one particle retainingstructure positioned to contact the directed flow of synovial fluid andconfigured to retain particles present within the synovial fluid.

In some aspects, a shoulder joint prosthesis includes: a bone-facingsurface of a shoulder joint prosthesis, the bone-facing surfaceconfigured to face a bone-prosthesis interface in vivo; a non-contactsurface of the shoulder joint prosthesis, the non-contact surfaceadjacent to the bone-facing surface of the shoulder joint prosthesis; atleast one fluid deflection structure attached to the non-contactsurface, the fluid deflection structure positioned to direct a flow ofsynovial fluid away from the bone-prosthesis interface in vivo; and atleast one particle retaining structure positioned to contact thedirected flow of synovial fluid and configured to retain particlespresent within the synovial fluid.

In addition to the foregoing, other aspects are described in the claims,drawings, and text forming a part of the disclosure set forth herein.The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a artificial hip joint in cross-section.

FIG. 2 depicts an artificial hip joint as in FIG. 1, with the joint bentas during physiological use.

FIG. 3 shows an artificial hip joint as in FIG. 1, in an external view.

FIG. 4 illustrates an artificial hip joint as in FIG. 2, in an externalview.

FIG. 5 depicts components of an artificial hip joint.

FIG. 6 shows a femoral component of an artificial hip joint.

FIG. 7A illustrates a femoral component of an artificial hip joint, witha plurality of fluid deflection structures attached.

FIG. 7B shows a closer view of a fluid deflection structure attached tothe femoral component of an artificial hip joint.

FIG. 8 depicts an external, frontal view of an artificial knee joint.

FIG. 9 shows a side view of an artificial knee joint as in FIG. 8.

FIG. 10 illustrates an artificial shoulder joint.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here.

Artificial joint prostheses are used as a surgical therapeuticsubstitute for joint components that are damaged, such as due to injuryor osteoarthritis. The goals of surgical implantation of artificialjoint prostheses generally include improving joint function andalleviating pain. Although these surgeries have a high success rate,there is some risk over time that an artificial joint prosthesis canfail. Failure of artificial prosthetic joints can require furthersurgery, with associated costs and morbidity for the patient. Oneclinically significant type of artificial joint failure is associatedwith loosening of the prosthesis at the bone interface, includingosteolysis and related damage to the bone.

Artificial joint prosthesis failure related to loosening of theprosthesis at the bone interface can have significant adverse clinicalconsequences. Patients can experience pain and reduced mobility, forexample, which can pose a problem for patients who are otherwise active.In addition, artificial joint prosthesis failure related to loosening ofthe prosthesis can pose a particular problem in younger patients whohave many years of expected lifespan ahead of them, with the associatedneed to preserve bone mass and joint function for the future. Thenegative consequences of prosthesis failure related to loosening of theprosthesis can also increase the medical burden of patients withsecondary medical problems. For example, reduced mobility fromprosthetic joint failure can be a significant problem for a person whouses exercise to control their high blood pressure. In some cases,surgical revision is required to address prosthesis failure related toloosening of the prosthesis, with associated costs and morbidity to thepatient. Although surgical revision rates vary by the type of prosthesisused and patient subgroup, a recent study of hip prosthesis failurerates found 5 year revision rates ranging from 1.6% to 6.1% (Smith etal., “Failure rates of Stemmed Metal-on-metal Hip Replacements: Analysisof Data from the National Joint Registry of England and Wales,” TheLancet, 379:1199-1204 (2012), which is incorporated herein byreference).

Artificial joint prosthesis failure is associated in a significantnumber of cases with loosening of the prosthesis at the prosthesis-jointinterface or in the periprosthetic region due to loss of the adjacentbone. This is believed to be caused in part from osteolysis promoted bythe body's response to debris from the artificial joint prosthesis. See,e.g. Linden, “Longer Life for Artificial Joints,” Nature 487: 179-180,(2012): and U.S. Pat. No. 5,378,228 “Method and Apparatus for JointFluid Decompression and Filtration with Particulate Debris Collection,”to Schmalzried and Jasty, which are each incorporated herein byreference. Wear debris from the prosthesis surface coming into contactwith the bone-prosthesis interface has been implicated, for example, inloosening of the prosthesis and associated failure. Debris particles atthe prosthesis-bone interface can contribute to osteolysis and resultingprosthesis loosening with potential failure of the prosthesis. Debrisparticles within the synovial fluid can include, for example, one ormore of: cellular debris particles; particulates of bone and prosthesisgenerated during surgery; and particulates formed from wear of theartificial joint prosthesis. Some studies indicate that debris particlescan enter the prosthesis-bone interface region through increasedsynovial fluid pressure at the prosthesis-joint interface duringphysiological movement. Some studies indicate that debris particles canenter the prosthesis-bone interface region through increased synovialfluid flow rate against the prosthesis joint interface duringphysiological movement. Studies also indicate that both fluid pressureand flow rate at the prosthesis-joint interface due to prosthesismovement during physiological activities encourage debris particles toenter the prosthesis-bone interface, contributing to osteolysis andprosthesis failure. See: Smith et al., ibid.; Fahlgren et al., “FluidPressure and Flow as a Cause of Bone Resorption,” Acta Orthopaedica81(4):508-516 (2010): Bartlett et al., “In Vitro Influence of StemSurface Finish and Mantle Conformity on Pressure Generation in CementedHip Arthroplasty,” Acta Orthopaedica 80(2): 139-143 (2009): Bartlett etal., “The Femoral Stem Pump in Cemented Hip Arthroplasty: an In VitroModel,” Medical Engineering and Physics, 30: 1042-1048 (2008): Agarwal,“Osteolysis—Basic Science, Incidence and Diagnosis,” CurrentOrthopaedics 18: 220-231 (2004); Manley et al., “Osteolysis: a Diseaseof Access to Fixation Interfaces,” Clinical Orthopaedics and RelatedResearch 405:129-137 (2002); and Anthony et al., “Localized EndostealBone Lysis in Relation to the Femoral Components of Cemented Total HipArthroplasties,” British Journal of Bone and Joint Surgery, 72-B(6):971-979 (1990), which are each incorporated herein by reference. Seealso: US Patent Application No. 2003/0014122 and U.S. Pat. No.6,569,202, each titled “Tray and Liner for Joint Replacement System,” toWhiteside; US Patent Application No. 2005/0055101 “Endoprosthesis of theKnee and/or other Joints,” to Sifneos; and US Patent Application No.2004/0068322, “Reduced-Friction Artificial Joints and ComponentsTherefor” to Ferree, which are each incorporated herein by reference.

The artificial joint prosthesis components described herein includesynovial fluid deflecting structures configured to divert synovial fluidflow away from the prosthesis-bone interface during physiologicalactivity. The artificial joint prosthesis components described hereininclude synovial fluid deflecting structures configured to divertsynovial fluid and debris particles within the fluid away from theprosthesis-bone interface. The synovial fluid deflecting structures ofthe artificial joint prosthesis components described herein are alsoconfigured to decrease the transient synovial fluid pressure at theprosthesis-bone interface during physiological activities. Theartificial joint prostheses described herein also include particleretaining structures configured to sequester particles from the fluidflow, thereby reducing the number of particles present in the jointfluid. The reduction of synovial fluid flow as well as transientpressure at the bone-prosthesis interface along with reduction ofparticles in the joint fluid will lead to a reduction of debrisparticles entering the prosthesis-bone interface during physiologicalmovement. This will decrease the risk of osteolysis related to weardebris particles at the prosthesis-bone interface, thereby reducing therisk of prosthesis failure and the need for revision surgery with itsassociated costs and morbidity. In some embodiments, the prosthesisstructures will include additional chemical inhibitors of osteolysis(see, e.g. Linden, ibid, and Mediero et al., “Adenosine A_(2A) ReceptorActivation Prevents Wear Particle-Induced Osteolysis,” ScienceTranslational Medicine 4(135ra65) (2012), which are each incorporatedherein by reference).

The artificial joint prosthesis components described herein also includeparticle retaining structures configured to retain non-physiologicalparticles present within the synovial fluid. The fluid deflectingstructures are configured, including in size, shape and position, tooperate in conjunction with the particle retaining structures. Forexample, a particle retaining structure can be positioned with a surfacefacing the expected fluid flow mediated by one or more fluid deflectingstructures. The configuration of particle retaining structure(s) inconjunction with fluid deflecting structure(s) on the artificial jointwill promote fluid flow past the facing surface of the particleretaining structure, increasing transfer of any particles present in thejoint fluid from the fluid to the particle retaining structure. Removalof particles by the particle retaining structure will decrease thosepresent in the synovial fluid, reducing the possibility that they willcontribute to osteolysis.

The artificial joint prosthesis components described herein includesynovial fluid deflecting structures configured to deflect synovialfluid flow away from the bone-prosthesis interface as well as tomitigate the transient increase in synovial fluid pressure at thebone-prosthesis interface during physiological movement (see, e.g. FIGS.2 and 4). The artificial joint prosthesis components described hereinalso include particle retention structures, positioned and shaped toretain particles present in the synovial fluid deflected by the fluiddeflecting structures. In some embodiments, there are synovial fluiddeflecting structures positioned on one component of an artificial jointprosthesis, and one or more associated particle retention structurespositioned on another component of the prosthesis. In some embodiments,there are synovial fluid deflecting structures positioned on two or morecomponents of an artificial joint prosthesis, with the synovial fluiddeflecting structures configured to work in combination with each otheras well as one or more particle retaining structures during relativemotion of the two or more components of an artificial joint prosthesisduring in vivo use (see, e.g. FIGS. 1-4).

In some embodiments, there are synovial fluid deflecting structuresconfigured to induce angular momentum in the synovial fluid duringphysiological movement. The induced angular momentum of the synovialfluid results in deflection of the synovial fluid flow away from thebone-prosthesis interface, and reduced transient pressure at thebone-prosthesis interface during physiological movement during in vivouse. The induced angular momentum of the synovial fluid also results indeflection of the synovial fluid flow toward a surface of a particleretaining structure during in vivo use. In some embodiments, there aresynovial fluid deflecting structures positioned on one or more of thejoint components and configured to convert the force from the jointmotion on the synovial fluid during physiological movement into aresulting synovial fluid flow in an inclined or orthogonal directionrelative to the original synovial fluid flow. The converted inclined ororthogonal direction of the synovial fluid results in deflection of thesynovial fluid flow away from the bone-prosthesis interface, and reducedtransient pressure at the bone-prosthesis interface during physiologicalmovement during in vivo use. One or more particle retention structuresare positioned relative to the expected deflection of synovial fluid bythe fluid deflecting structures. The specific positioning, size, shapeand configuration of the synovial fluid deflecting structures on theartificial joint prosthesis components will vary depending on theembodiment, including the specific type of artificial joint prosthesis,its size, the size of the associated joint in vivo, and expectedphysiological forces on the associated synovial fluid when theartificial joint prosthesis is used in vivo. Similarly, the specificpositioning, size, shape and configuration of one or more particleretaining structures will vary depending on the embodiment, includingthe specific type of artificial joint prosthesis, its size, the size ofthe associated joint in vivo, and the expected patterns of synovialfluid flow during physiological use of the prosthetic joint.

The material used to fabricate a synovial fluid deflection structurewill vary depending on the embodiment. Factors in the selection ofmaterials for a fluid deflection structure include: cost of thematerials, size of the fluid deflection structure, shape of the fluiddeflection structure, flexibility of the fluid deflection structureunder the estimated physiological pressure of synovial fluid in a givenembodiment, and compatibility of the fluid deflection structure withother components of the prosthetic implant. Materials used to fabricatea fluid deflection structure will be part of the prosthetic joint, andtherefore should be suitable for implantation into a body (e.g. lowtoxicity and non-inflammatory). Materials used to fabricate a fluiddeflection structure should be expected to be durable throughout theanticipated duration of use of the prosthetic joint, for example no lessthan 10 years of routine physiological use in vivo. Materials suitablefor fabrication of a synovial fluid deflection structure include, forexample, polypropylene and silicone.

The material used to fabricate a particle retaining structure will alsovary depending on the embodiment. Factors in the selection of materialsfor a particle retaining structure include: cost of the materials, sizeof the particle retaining structure, shape of the particle retainingstructure, stability of the particle retaining structure under theestimated physiological pressure of synovial fluid and joint motion in agiven embodiment, and compatibility of the particle retaining structurewith other components of the prosthetic implant. In some embodiments, aparticle retaining structure is configured to surround the joint, (e.g.as a membrane configured as a sheath or tube around the joint andaffixed at both ends to the artificial joint). A particle retainingstructure can include components designed to ease the use of the joint,such as ring structures configured to encourage folding of the membraneduring joint movement. See U.S. Pat. No. 5,514,182 “Prosthetic Jointwith Semipermeable Capsule with Reinforcing Ribs,” to Shea, which isincorporated herein by reference. Materials used to fabricate a particleretaining structure will be part of the prosthetic joint, and thereforeshould be suitable for implantation into a body (e.g. low toxicity andnon-inflammatory). Materials used to fabricate a particle retainingstructure should be expected to be durable throughout the anticipatedduration of use of the prosthetic joint, for example no less than 10years of routine physiological use in vivo. Materials suitable forfabrication of a particle retaining structure include, for example,silicone, hydroxyl-ethyl-methacrylate and polyvinylpirrolidone.

Although the artificial joint prostheses are described herein primarilyin reference to humans, in some embodiments the artificial jointprostheses as described herein will also have applicability inveterinary medicine. For example, aspects of the artificial hip jointprosthesis as described herein (see, e.g. FIGS. 1-7 and associated text)have applicability in hip joint replacements in domestic animals, suchas dogs and cats.

In some embodiments, an artificial joint prosthesis includes: abone-facing surface of a artificial joint prosthesis, the bone-facingsurface configured to face a bone-prosthesis interface in vivo; anon-load bearing surface of the artificial joint prosthesis, thenon-load bearing surface adjacent to the bone-facing surface of theartificial joint prosthesis; at least one fluid deflection structureattached to the non-load bearing surface, the fluid deflection structurepositioned to direct a flow of synovial fluid away from thebone-prosthesis interface in vivo during physiological movement of theartificial joint prosthesis; and at least one particle retainingstructure positioned to contact the directed flow of synovial fluid andconfigured to retain non-physiological particles present within thesynovial fluid. As used herein, the “non-load bearing surface” of anartificial joint prosthesis is a surface expected to not bear asignificant load, such as the person's mass, during routine movementutilizing normal physiological activities. For example, the edge of aacetabular liner in a hip joint prosthesis is generally expected to benon-load bearing during routine movement utilizing normal physiologicalactivity, although the edge of an acetabular liner in a hip jointprosthesis may become load bearing during an extreme physiologicalevent, such as hip joint dislocation. For example, the edge of a humeruscomponent in a shoulder joint prosthesis is generally expected to benon-load bearing during routine movement utilizing normal physiologicalactivity, although the edge of a humerus component in a shoulder jointprosthesis may become load bearing during an extreme physiologicalevent, such as shoulder joint dislocation. The specific regions of anartificial joint prosthesis that would be expected to be a “non-loadbearing surface” depend on the specific type of artificial joint, itssize and position during in vivo use.

In some embodiments, an artificial joint prosthesis includes: abone-facing surface of a artificial joint prosthesis, the bone-facingsurface configured to face a bone-prosthesis interface in vivo; anon-contact surface of the artificial joint prosthesis, the non-contactsurface adjacent to the bone-facing surface of the artificial jointprosthesis; at least one fluid deflection structure attached to thenon-contact surface, the fluid deflection structure positioned to directa flow of synovial fluid away from the bone-prosthesis interface invivo; and at least one particle retaining structure positioned tocontact the directed flow of synovial fluid and configured to retainparticles present within the synovial fluid.

As used herein, a “non-contact surface” of an artificial jointprosthesis refers to a surface of a component of the artificial jointprosthesis that is expected to not come into contact with the bone andalso to not come into contact with a surface of another component of theartificial joint prosthesis during normal physiological use of theartificial joint prosthesis in vivo. Specific examples of non-contactsurfaces are shown in the Figures, and discussed in the relevant textassociated with each Figure. The artificial joint prosthesis can includeat least one of: a hip joint prosthesis, a knee joint prosthesis, ashoulder joint prosthesis, an ankle joint prosthesis, or an elbow jointprosthesis. See, for example, FIGS. 1-10 and associated text. Thenon-contact surface of the artificial joint prosthesis is a surface ofthe prosthesis that is expected to not have contact with bone surfacesof the joint or other surfaces of the joint prosthesis during routinephysiological movement in vivo. For example, FIG. 5 depicts componentsof a hip prosthesis including fluid deflection structures positioned onsome non-contact surfaces. In some embodiments wherein the prosthesis isfor a hip joint, the non-contact surface of the artificial jointprosthesis can include at least one of: a region of a shell of aacetabular component of a hip joint prosthesis; a region of a liner of aacetabular component of a hip joint prosthesis; a region of a head of afemoral component of a hip joint prosthesis, or a region of a stem of afemoral component of a hip joint prosthesis. In some embodiments whereinthe prosthesis is for a knee joint, the non-contact surface of theartificial joint prosthesis can include at least one of: a region of afemoral component of a knee joint prosthesis; a region of a tibialspacer of a knee joint prosthesis; a region of a tibial component of aknee joint prosthesis; or a region of a component of a patellarcomponent of a knee joint prosthesis. In some embodiments wherein theprosthesis is for a shoulder joint, the non-contact surface of theartificial joint prosthesis can include at least one of: a region of ahumeral stem of a shoulder joint prosthesis; a region of a humeralspacer of a shoulder joint prosthesis; a region of a humeral head of ashoulder joint prosthesis; or a region of a glenoid component of ashoulder joint prosthesis.

In some embodiments, an artificial joint prosthesis includes at leastone fluid deflection structure positioned on the non-contact surface,wherein the at least one fluid deflection structure includes at leastone flange structure positioned to extend from the non-contact surface.The fluid deflection structure is configured to deflect synovial fluidtoward a particle retaining structure, as described herein. In someembodiments, a fluid deflection structure positioned on the non-contactsurface is configured as at least one flange structure positioned toextend from the non-contact surface. For example, a flange structure canbe configured as a projecting rim or collar from the non-contactsurface. For example, a flange structure can be configured as a one ormore ridges attached to the non-contact surface. The relative size andshape of the flange structure will vary by the specific type ofartificial joint (e.g. hip, knee, shoulder), the flexibility of thematerial used in construction of the flange structure, and the size ofthe artificial joint (e.g. relative to the size of the patient and thesize of the implant required for therapeutic correction of their joint).In some embodiments, the flange structure can form a ring to encirclethe entirety of a non-contact surface. In some embodiments, the flangestructure can form a rim or collar along the entirety of a non-contactsurface, or along a partial edge of a non-contact surface. In someembodiments, the flange structure can include a series of smallerstructures, such as a plurality of projections.

The at least one flange structure can be positioned to extend from thenon-contact surface at an angle predicted to mitigate synovial fluidflow rate and transient fluid pressure at the location of thebone-prosthesis interface. The angle of a flange structure projectingfrom the non-contact surface suitable to deflect synovial fluid flow andreduce transient synovial fluid pressure at the bone-prosthesisinterface will depend on the configuration of the artificial jointprosthesis in a specific embodiment, including, for example, the numberof flange structures, their relative positioning on the artificial jointprosthesis, the size and shape of the flange structures, and the size ofthe joint in vivo. For example, in some embodiments the at least oneflange structure can be positioned to extend from the non-contactsurface at an angle substantially between 10 degrees and 80 degrees of aplane established by the contact surface and relative to the bone-facingsurface of the artificial joint prosthesis. For example, in someembodiments the at least one flange structure can be positioned toextend from the non-contact surface at an angle substantially between100 degrees and 170 degrees of a plane established by the contactsurface and relative to the bone-facing surface of the artificial jointprosthesis. For example, in some embodiments the at least one flangestructure can be positioned to extend from the non-contact surface at asubstantially right angle from a plane established by the contactsurface and relative to the bone-facing surface of the artificial jointprosthesis.

In some embodiments wherein the at least one fluid deflection structurepositioned on the non-contact surface includes at least one flangestructure positioned to extend from the non-contact surface, the atleast one flange structure can include a first end connected to thenon-contact surface and a second end distal to the non-contact surface,wherein the flange structure is widest at the first end and narrowest atthe second end. See, for example, FIGS. 1-4. The at least one flangestructure can include at least one flange structure with a first endconnected to the non-contact surface and a second end distal to thenon-contact surface, wherein the flange structure tapers from a widestpoint at the first end to a narrow point at the second end. See, forexample, FIGS. 1-4. In some embodiments, the at least one fluiddeflection structure includes at least one flange structure with acurvilinear structure. For example, the flange structure can include athin, substantially curved structure, such as a crescent moon-shapedstructure. See, for example, FIGS. 1-4. In some embodiments, the atleast one fluid deflection structure includes at least one flangestructure with a significantly straight structure. See, for example,FIG. 5.

In some embodiments, the at least one fluid deflection structurepositioned on the non-contact surface includes at least one fluiddeflection structure with a first end connected to the non-contactsurface and a second end distal to the non-contact surface. In someembodiments, the at least one fluid deflection structure positioned onthe non-contact surface includes a plurality of linear projections. Forexample, the linear projections can be hair-like or ciliated. See, forexample, FIG. 5. The linear projections are attached to the non-contactsurface at an angle appropriate to divert part of the flow of synovialfluid away from the bone-prosthesis interface and toward a particleretaining structure, as well as to reduce synovial fluid pressure at thebone-prosthesis interface during physiological movement. The size,shape, and attachment angle of the linear projections will, therefore,vary by the specific embodiment. For example, in embodiments wherein theat least one fluid deflection structure includes a plurality of linearprojections, the linear projections can be positioned to extend from thenon-contact surface at an angle substantially between 10 degrees and 80degrees of a plane established by the contact surface and relative tothe bone-facing surface of the artificial joint prosthesis. For example,in embodiments wherein the at least one fluid deflection structureincludes a plurality of linear projections, the plurality of linearprojections can be positioned to extend from the non-contact surface atan angle substantially between 100 degrees and 170 degrees of a planeestablished by the contact surface and relative to the bone-facingsurface of the artificial joint prosthesis. For example, in embodimentswherein the at least one fluid deflection structure includes a pluralityof linear projections, the plurality of linear projections can bepositioned to extend from the non-contact surface at an substantiallyright angle from a plane established by the contact surface and relativeto the bone-facing surface of the artificial joint prosthesis.

The at least one fluid deflection structure positioned on thenon-contact surface is positioned relative to the non-contact surface atan angle appropriate to divert part of the flow of synovial fluid awayfrom the bone-prosthesis interface and toward a particle retainingstructure, as well as to reduce synovial fluid pressure at thebone-prosthesis interface during physiological movement. The size,shape, and attachment angle of the at least one fluid deflectionstructure will, therefore, vary by the specific embodiment. Someembodiments include at least one fluid deflection structure attached toa single component of the artificial joint prosthesis. Some embodimentsinclude at least two components of the artificial joint prosthesis, eachof which include at least one fluid deflection structure positioned on anon-contact surface of the artificial joint prosthesis. For example, insome embodiments the at least one fluid deflection structure includes asubstantially straight fluid deflection structure. For example, in someembodiments the at least one fluid deflection structure includes asubstantially curved fluid deflection structure.

Similarly, the rigidity of a synovial fluid deflection structure willvary depending on the embodiment, relative to factors such as thespecific type of joint, its size, the expected flow dynamics of synovialfluid through the joint during in vivo use, the position of the synovialfluid deflection structure on the prosthesis, and the shape of thesynovial fluid deflection structure. In some embodiments, the at leastone fluid deflection structure positioned on the non-contact surface isconfigured to be substantially rigid at physiological conditions whenthe artificial joint is utilized in vivo. In some embodiments, the atleast one fluid deflection structure positioned on the non-contactsurface is configured to be flexible at physiological conditions whenthe artificial joint is utilized in vivo. In some embodiments, the atleast one fluid deflection structure positioned on the non-contactsurface is configured to flex to a degree sufficient to permit a largersynovial fluid flow rate away from the bone-prosthesis interface duringperiods of increased synovial fluid pressure in the region of thenon-contact surface when the artificial joint is utilized in vivo atphysiological conditions, and to permit a smaller synovial fluid flowrate away from the bone-prosthesis interface during periods of reducedsynovial fluid pressure when the artificial joint is utilized in vivo atphysiological conditions. In some embodiments, the at least one fluiddeflection structure positioned on the non-contact surface is configuredto flex to a degree sufficient to permit an increased synovial fluidflow rate away from the bone-prosthesis interface in response toincreased fluid pressure in a region adjacent to the bone-prosthesisinterface.

Some embodiments include a particle retaining structure that isconfigured as a substantially planar structure. For example, a particleretaining structure can be configured as an attachment to theprosthesis, with a surface substantially mating with another surface ofthe prosthesis. See, e.g. FIG. 5. Some embodiments include a particleretaining structure that includes a mesh-like structure. For example, aparticle retaining structure can be configured as a membrane surroundingthe joint, with the particle retaining structure including a mesh-likestructure configured to allow synovial fluid flow through the membrane.Some embodiments include a particle retaining structure that includes afilter structure. For example, a particle retaining structure can beconfigured as a 3-dimensional filter. Some embodiments include aparticle retaining structure that includes a foam structure. Forexample, a particle retaining structure including a foam structure caninclude a surface configured to mate with a surface of the prosthesis,and a surface configured to retain particles in the foam structure. Forexample, a particle retaining structure including a foam structure canbe configured to absorb particles from fluid flow directed at the foamstructure by one or more fluid deflecting structures attached to thejoint.

Some embodiments include a particle retaining structure that includes agroup of projections, each of the projections positioned to contact theflow of synovial fluid and configured to retain particles present withinthe synovial fluid. For example, a particle retaining structure thatincludes a group of projections can include a coating on the externalsurfaces of the projections, the coating configured to trap any debrisparticles present in the fluid flow around the projections. For example,a particle retaining structure that includes a group of projections caninclude an adhesive coating on the external surface of the projections.For example, a particle retaining structure that includes a group ofprojections can include a hydrophobic coating on the external surface ofthe projections, the hydrophobic coating configured to attracthydrophobic particles in the joint fluid, such as hydrophobic plasticparticles. For example, a particle retaining structure that includes agroup of projections can include at least one type of antibody affixedto the external surfaces of the projections, the antibody of a sizeexpected to bind to particulates within the joint fluid.

Some embodiments include a particle retaining structure that includes afirst end, the first end affixed to the artificial joint prosthesis; anda second end, the second end affixed to an additional artificial jointcomponent. For example, a particle retaining structure can include oneor more membrane structures, each of which include a first end affixedto the artificial joint prosthesis, such as the acetabular liner of ahip joint, and a second end affixed to an additional artificial jointcomponent, such as the region adjacent to the prosthesis-bone interfaceon the femoral component of the prosthesis. Some embodiments include aparticle retaining structure that is affixed to a surface of theartificial joint prosthesis. For example, a particle retaining structurecan be configured to reversibly mate with a surface of one or morecomponents of a artificial joint. See, for example, FIG. 5. Someembodiments include a particle retaining structure that is affixed to aplurality of surfaces of the artificial joint prosthesis. Someembodiments include a particle retaining structure that is affixed to aplurality of components of the artificial joint prosthesis. See, forexample, FIGS. 1-4.

Some embodiments include at least one particle retaining structureincluding a plurality of apertures. For example, the plurality ofapertures can be configured to be of a size and shape to physicallyentrap the expected particles in the joint fluid. For example, aparticle retaining structure can include a plurality of apertures havinga diameter less than approximately 0.05 millimeters (mm). See, forexample, U.S. Pat. No. 5,378,228 “Method and Apparatus for Joint FluidDecompression and Filtration with Particulate Debris Collection,” toSchmalzried and Jasty, which is incorporated herein by reference. Someembodiments include at least one particle retaining structure includinga structure configured to retain non-physiological particles present inthe synovial fluid. For example, the structure configured to retainnon-physiological particles present in the synovial fluid can includeapertures of the correct size and shape to retain the expectednon-physiological particles in the synovial fluid. For example, thestructure configured to retain non-physiological particles present inthe synovial fluid can include a coating expected to bind tonon-physiological particles, such as a coating including one or moreantibodies, or a coating containing one or more chemically reactivespecies. Some embodiments include at least one particle retainingstructure including a structure configured to retain particlescontaining artificial materials. For example, the structure configuredto retain non-physiological particles present in the synovial fluid caninclude a magnetic coating configured to bind ferromagnetic particlespresent in the fluid.

Some embodiments include a artificial joint prosthesis including atleast two components, each of which include at least one fluiddeflection structure positioned on a non-contact surface. See, forexample, FIGS. 1-4. Some embodiments include at least two components: afirst component which includes at least one fluid deflection structureaffixed to a non-contact surface; and a second component which includesat least one particle retaining structure affixed to a surface. Thefirst component and the second component are positioned, sized andfabricated from materials selected to be compatible with each other. Forexample, the fluid deflection structure affixed to a non-contact surfaceof the first component is of a size, shape and position to deflect jointfluid flow towards the particle retaining structure affixed to thesurface of the second component. For example, the fluid deflectionstructure affixed to a non-contact surface of the first component is ofa size, shape and position to deflect joint fluid flow away from an exitstructure of a particle retaining structure configured for linear fluidflow and affixed to the surface of the second component.

For a more complete understanding of the embodiments, reference now ismade to the following descriptions taken in connection with theaccompanying drawings. The use of the same symbols in different drawingstypically indicates similar or identical items, unless context indicatesotherwise.

With reference now to FIG. 1, shown is an example of an artificial hipjoint prosthesis depicted in vivo in cross-section that serves as acontext for introducing one or more artificial joint prosthesesincluding fluid deflecting structures as described herein. Theartificial hip joint prosthesis depicted in FIG. 1 is depicted incross-section in vivo in a resting, or not significantly physiologicallyflexed, position. The cross-section view depicted in FIG. 1 is asubstantially planar view of a vertical cross-section through the hipjoint. The embodiment illustrated in FIG. 1 includes a hip jointprosthesis including: a bone-facing surface of a hip joint prosthesis,the bone-facing surface configured to face a bone-prosthesis interfacein vivo; a non-contact surface of the hip joint prosthesis, thenon-contact surface adjacent to the bone-facing surface of the hip jointprosthesis; at least one fluid deflection structure positioned on thenon-contact surface, the fluid deflection structure positioned todeflect synovial fluid away from the bone-prosthesis interface in vivo;and at least one particle retaining structure positioned to contact thedirected flow of synovial fluid and configured to retain particlespresent within the synovial fluid.

FIG. 1 illustrates a hip joint prosthesis 100 in vivo, with prostheticcomponents including an acetabular shell 170, and acetabular liner 175,and a femoral component. The femoral component includes a femoral headcomponent 182 and a femoral stem component 187. In some contexts, anacetabular shell 170 is referred to as an acetabular cup. A synovialmembrane 190 forms the boundary of the joint region that includessynovial fluid. A particle retaining structure 195 is formed as amembrane-like structure surrounding the joint, within the boundary ofthe synovial membrane 190. The prosthetic components 170, 175, 182, 187are respectively attached to a pelvic bone 160 and femur 150. Theacetabular liner 175 includes a bone-facing surface 110. The acetabularshell 170 includes a bone-facing surface 112. The femoral stem component187 includes a bone-facing surface 115. The bone-facing surfaces 110,112, 115 of the prosthetic components 170, 175, 187 in contact with thebone form bone-prosthesis interfaces 120 in vivo. The particle retainingstructure 195 is attached to a surface of the femoral stem 187 at oneend of the particle retaining structure 195 and to a surface of theacetabular liner 175 at the other end of the particle retainingstructure 195. In some embodiments wherein the particle retainingstructure 195 is attached to two components of the hip prosthesis asillustrated in FIG. 1, the particle retaining structure 195 includes oneor more collapsible structures. See U.S. Pat. No. 5,514,182 “ProstheticJoint with Semipermeable Capsule with Reinforcing Ribs,” to Shea, whichis incorporated herein by reference.

The hip joint prosthesis 100 of FIG. 1 includes several regions withnon-contact surfaces. As shown in FIG. 1, the acetabular liner 175includes an edge region with a non-contact surface 130. The non-contactsurface 130 of the acetabular liner 175 is a surface of the acetabularliner 175 that is predicted to not come in contact with the bone (e.g.the pelvis 160) or a surface of another component of the artificial hipjoint (e.g. the femoral head 182) during normal physiological use invivo. The non-contact surface 130 of the acetabular liner 175 includesattached synovial fluid deflecting structures 140. In some embodiments,the non-contact surface of an artificial hip prosthesis includes an edgeregion of a liner of a acetabular component of the hip joint prosthesis.In some embodiments, the non-contact surface of an artificial hipprosthesis includes an edge region of a shell of a acetabular componentof the hip joint prosthesis. Also as shown in FIG. 1, the femoral stem187 includes a region with a non-contact surface 135. The non-contactsurface 135 of the femoral stem 187 is a surface of the femoral stem 187that is predicted to not come in contact with the bone (e.g. the femur150) or a surface of another component of the artificial hip joint (e.g.the acetabular liner 175) during normal physiological use in vivo. Thenon-contact surface 135 of the femoral stem 187 includes attachedsynovial fluid deflecting structures 145. In some embodiments, thenon-contact surface of an artificial hip prosthesis includes an edgeregion of a head of a femoral component of the hip joint prosthesis(see, e.g. FIG. 5). In some embodiments, the non-contact surface of anartificial hip prosthesis includes an edge region of a stem of a femoralcomponent of the hip joint prosthesis.

FIG. 1 illustrates that some embodiments include a plurality of fluiddeflection structures 140, 145 positioned on more than one non-contactsurface 130, 135 of the artificial hip prosthesis. In some embodiments,only one region with a non-contact surface has attached one or morefluid deflection structures. For example, in some embodiments, fluiddeflection structures 140 are attached to only the non-contact surface130 of the acetabular liner 175. For example, in some embodiments, fluiddeflection structures 145 are attached to only the non-contact surface135 of the femoral stem 187. The fluid deflection structures 140, 145are positioned to direct joint fluid flow toward the particle retainingstructure 195.

In some embodiments, the at least one fluid deflection structurepositioned on the non-contact surface of an artificial hip prosthesisincludes at least one flange structure positioned to extend from thenon-contact surface. The flange structure is of a size and shape todeflect synovial fluid flow away from one or more of the bone-prosthesisinterfaces 120 in vivo and to direct synovial fluid flow toward theparticle retaining structure 195. The flange structure is of a size andshape to mitigate synovial fluid pressure at one or more of thebone-prosthesis interfaces 120 in vivo during physiological use of thejoint. For example, in some embodiments, the at least one flangestructure is positioned to extend from the non-contact surface at anangle substantially between 10 degrees and 80 degrees of a planeestablished by the contact surface and relative to the bone-facingsurface of the hip joint prosthesis. For example, in some embodiments,the at least one flange structure is positioned to extend from thenon-contact surface at an angle substantially between 100 degrees and170 degrees of a plane established by the contact surface and relativeto the bone-facing surface of the hip joint prosthesis. For example, insome embodiments, the at least one flange structure is positioned toextend from the non-contact surface at a substantially right angle froma plane established by the contact surface and relative to thebone-facing surface of the hip joint prosthesis. The flange structurecan include a first end connected to the non-contact surface and asecond end distal to the non-contact surface, wherein the flangestructure is widest at the first end and narrowest at the second end.The flange structure can include a first end connected to thenon-contact surface and a second end distal to the non-contact surface,wherein the flange structure tapers from a widest point at the first endto a narrow point at the second end. The flange structure can include atleast one flange structure with a curvilinear structure. The flangestructure can include at least one flange structure with a substantiallyflat or linear structure when not under pressure from synovial fluid,and a curvilinear structure when under pressure.

As shown in FIG. 1, a fluid deflection structure 140, 145 can include afirst end connected to the non-contact surface and a second end distalto the non-contact surface. In some embodiments, a fluid deflectionstructure can include a substantially planar structure. In someembodiments, a fluid deflection structure can include a tapered orangular structure. In some embodiments, a fluid deflection structure caninclude a collar structure around an edge of a non-contact surface. Asshown in FIG. 1, some embodiments include a plurality of fluiddeflection structures 140, 145 configured to direct synovial fluid flowtoward a single particulate retaining structure 195. Some embodimentsinclude at least one acetabular component 175, wherein the acetabularcomponent 175 includes at least one fluid deflection structure 140positioned on the non-contact surface 130; and at least one femoral stem187, wherein the femoral stem 187 includes at least one fluid deflectionstructure 145 positioned on the non-contact surface 135.

In some embodiments, a fluid deflection structure can include aplurality of linear projections. For example, a fluid deflectionstructure can include one or more hair-like or ciliated structures. Theplurality of linear projections are of a size and shape so that thelinear projections, in the aggregate, deflect synovial fluid flow awayfrom one or more of the bone-prosthesis interfaces 120 in vivo anddirect synovial fluid flow toward the particulate retaining structure195. The specific size and number of linear projections will depend onthe embodiment, relative to factors including the size of the joint, theestimated synovial fluid pressure in the joint during physiological use,and the flexibility of the material used to fabricate the fluiddeflection structure including a plurality of linear projections. Thespecific size and number of linear projections will depend on the size,shape and position of the one or more particulate retaining structure195 in the embodiment. In some embodiments, the plurality of linearprojections are positioned to extend from the non-contact surface at anangle substantially between 10 degrees and 80 degrees of a planeestablished by the contact surface and relative to the bone-facingsurface of the hip joint prosthesis. In some embodiments, the pluralityof linear projections are positioned to extend from the non-contactsurface at an angle substantially between 100 degrees and 170 degrees ofa plane established by the contact surface and relative to thebone-facing surface of the hip joint prosthesis. In some embodiments,the plurality of linear projections are positioned to extend from thenon-contact surface at an substantially right angle from a planeestablished by the contact surface and relative to the bone-facingsurface of the hip joint prosthesis.

Some embodiments include at least one fluid deflection structurepositioned on the non-contact surface including a substantially straightfluid deflection structure. The substantially straight fluid deflectionstructure can be, for example, substantially linear or substantiallyplanar. The substantially straight fluid deflection structure can be,for example, substantially straight in the absence of synovial fluidpressure but flex or bend in the presence of synovial fluid pressureduring in vivo use of the artificial hip joint. Some embodiments includeat least one fluid deflection structure positioned on the non-contactsurface including a substantially curved fluid deflection structure. Thesubstantially curved fluid deflection structure can further curve orbend in the presence of synovial fluid pressure during in vivo use ofthe artificial hip joint.

In some embodiments, a fluid deflection structure of any initial shapecan be configured to be substantially rigid at physiological conditionswhen the artificial joint is utilized in vivo. For example, a fluiddeflection structure can be fabricated from a material in a suitablesize and shape that is expected to be substantially rigid during in vivouse of the artificial hip joint prosthesis. The rigidity of a fluiddeflection structure may be desirable, for example to enhance angularmomentum in the synovial fluid.

In some embodiments, a fluid deflection structure of any initial shapecan be configured to be flexible at physiological conditions when theartificial joint is utilized in vivo. For example, a fluid deflectionstructure can be fabricated from a material in a suitable size and shapethat is expected to be flexible during in vivo use of the artificial hipjoint prosthesis. The flexibility of a fluid deflection structure may bedesirable, for example, to convert the fluid pressure resulting fromjoint motion in one direction into synovial fluid motion in an inclinedor orthogonal direction during use of the artificial hip jointprosthesis. For example, in some embodiments the at least one fluiddeflection structure positioned on the non-contact surface can beconfigured to flex to a degree sufficient to permit a larger synovialfluid flow rate away from the bone-prosthesis interface during periodsof increased synovial fluid pressure in the region of the non-contactsurface when the artificial joint is utilized in vivo at physiologicalconditions, and to permit a smaller synovial fluid flow rate away fromthe bone-prosthesis interface during periods of reduced synovial fluidpressure when the artificial joint is utilized in vivo at physiologicalconditions. For example, in some embodiments the at least one fluiddeflection structure positioned on the non-contact surface is configuredto flex to a degree sufficient to permit an increased synovial fluidflow rate away from the bone-prosthesis interface in response toincreased fluid pressure in a region adjacent to the bone-prosthesisinterface.

FIG. 1 illustrates a particle retaining structure 195 configured as asheath surrounding the joint, the sheath having a first end connected tothe femoral stem 187 and the second end connected to the acetabularliner 175. The particle retaining structure 195 illustrated in FIG. 1 isconfigured to allow synovial fluid to pass through the structure, whileretaining particles from the fluid flow on the structure. Not allparticles need be retained by the particle retaining structure 195. Someembodiments include particle retaining structures that are configured toonly sequester some types of particles, depending on their physicalproperties. Some embodiments include particle retaining structures thatinclude a plurality of apertures. For example, particle retainingstructures including apertures will not sequester particles too large ortoo small to be sequestered within the apertures. For example, particleretaining structures including magnetic elements will sequesterferromagnetic particles, and not inhibit non-ferromagnetic particles.For example, particle retaining structures including antibodies willsequester particles with surface molecules that bind the antibodies, andnot retain particles that do not include surface molecules that bind theantibodies. For example, particle retaining structures including ahydrophobic surface will sequester particles with surface molecules thatinteract with the hydrophobic surface, and not retain particles that donot include surface molecules that interact with the hydrophobicsurface. Some embodiments include particle retaining structures thatinclude a mesh-like structure, for example with apertures thatphysically entrap particles of a specific size range. Some embodimentsinclude particle retaining structures that include a filter structure,for example with channels that physically entrap particles of a specificsize range. Some embodiments include particle retaining structures thatinclude a foam structure, for example foam with a surface adhesiveconfigured to adhere to particles physically pressed against the foam bythe deflected flow of the joint fluid. Some embodiments include particleretaining structures that include a structure configured to retainnon-physiological particles present in the synovial fluid, for examplethrough specific binding to chemical elements present on the surface ofthe particle retaining structure. Some embodiments include particleretaining structures that include a structure configured to retainparticles including artificial materials. For example, a particleretaining structure can include one or more chemical elements configuredto bind to specific artificial materials (e.g. plastics or ceramics).For example, a particle retaining structure can include a magnetizedsurface configured to capture ferromagnetic particles. In someembodiments, a particle retaining structure is configured to captureparticles through multiple means (e.g. with a magnetized surface as wellas a set of apertures configured to sequester particles of a specificsize range).

Some embodiments include particle retaining structures that areconfigured as substantially planar structures. For example, a particleretaining structure having a first end connected to the femoral stem 187and the second end connected to the acetabular liner 175 as illustratedin FIG. 1 can be configured with the particle retaining structureincluding a series of substantially planar structures, each with aconnected first end and second end. As an additional example, a particleretaining structure can be configured as a substantially planarstructure including a surface configured to mate with a surface of acomponent of the prosthesis. See, e.g. FIG. 5.

Some embodiments include particle retaining structures as a group ofprojections. Each of the projections can be positioned to contact theflow of synovial fluid and configured to retain particles present withinthe synovial fluid. The group of projections can be shaped assubstantially linear projections, for example as hair-like or ciliatedstructures. The group of projections include surfaces structured to bindand sequester particles from the joint fluid. The projections can befabricated to bind some particles in the joint fluid based on thestructure of specific particles. For example, the particle retainingstructures configured as projections can include hydrophobic surfaces.For example, the particle retaining structures configured as projectionscan include surfaces with attached antibodies. For example, the particleretaining structures configured as projections can include magneticsurfaces. Some embodiments include particle retaining structuresconfigured as projections with different types of surfaces. For example,a group of projections can include magnetized surfaces as well as thoseincluding specific antibodies.

In some embodiments, at least one particle retaining structure isaffixed to a surface of the hip joint prosthesis. In some embodiments,at least one particle retaining structure is affixed to a plurality ofsurfaces of the hip joint prosthesis. In some embodiments, at least oneparticle retaining structure is affixed to a plurality of components ofthe hip joint prosthesis. See, e.g. FIGS. 1-4 as associated text.

FIG. 2 illustrates aspects of the artificial hip joint prosthesisembodiment as shown in FIG. 1. The artificial hip joint prosthesis 100depicted in FIG. 2 is depicted in cross-section in vivo in a flexed orbent position. As in FIG. 1, the view depicted in FIG. 2 is asubstantially planar view of a vertical cross-section through the hipjoint in vivo. As illustrated in FIG. 2, the artificial hip jointprosthesis 100 includes an acetabular shell 170, an acetabular liner 175and a femoral component including a femoral head 182 and femoral stem187. A particle retaining structure 195 is formed as a membrane-likestructure surrounding the joint and attached to both the acetabularliner 175 and the femoral component. A particle retaining structure 195as illustrated can be formed with a mesh structure including aperturesof a size and shape to sequester particles of a size range (e.g. 0.05 to0.01 mm). The particle retaining structure 195 lies within the boundaryof the synovial membrane 190, and therefore within the expected flow ofsynovial joint fluid in vivo.

FIG. 2 depicts the joint in a flexed position, which is expected toresult in a transient increase in synovial fluid pressure at thebone-prosthesis interface regions put into closer proximity during thejoint repositioning. For example, FIG. 2 illustrates that regions of thenon-contact surface 130A of the acetabular liner 175 and a region of thenon-contact surface 135A of the femoral stem 187 are being placed incloser proximity due to the joint repositioning (e.g. relative to thejoint position illustrated in FIG. 1). Correspondingly, FIG. 2 showsthat regions of the non-contact surface 130B of the acetabular liner 175and a region of the non-contact surface 135B of the femoral stem 187 aremoved away from each other due to the joint repositioning (e.g. relativeto the joint position illustrated in FIG. 1). The particle retainingstructure 195 is configured to bend or shift in accord with the joint.

For a transient period during and immediately after the joint flexing orbending from the position illustrated in FIG. 1 to the positionillustrated in FIG. 2, there is an increase in synovial fluid pressurein the region between the non-contact surface 130A of the acetabularliner 175 and a region of the non-contact surface 135A of the femoralstem 187. This results in an increased synovial fluid flow across thejoint, as illustrated by the dotted arrows across the artificial joint100 in FIG. 2. The joint bending, and the associated localized synovialfluid pressure increase, results in the flexing of the fluid deflectingstructures 140A attached to the non-contact surface 130A of theacetabular liner 175. The joint bending, and the associated localizedsynovial fluid pressure increase, also results in the flexing of thefluid deflecting structures 145A attached to the non-contact surface135A of the femoral stem 187. The fluid deflecting structures 140 B,145B attached to the non-contact surfaces 130B, 135B of the acetabularliner 175 and the femoral stem 187 not subject to increased synovialfluid pressure do not bend or flex in the same manner as the fluiddeflecting structures 140A, 145A subject to the localized synovial fluidpressure increase associated with the joint bending. The increasedsynovial fluid flow across the joint, as illustrated by the dottedarrows across the artificial joint 100 in FIG. 2, direct the flow ofjoint fluid toward a surface of the particle retaining structure 195.Particulates in the fluid flow coming into contact with the particleretaining structure 195 are sequestered on the surface of or within thestructure of the particle retaining structure 195.

FIG. 3 illustrates a hip joint prosthesis 100 in vivo, with prostheticcomponents including an acetabular liner 175, and a femoral stem 187.The embodiment depicted in FIG. 3 is similar to that shown in FIG. 1from an external viewpoint. The view illustrated in FIG. 3 is a view ofthe artificial hip joint prosthesis in vivo in a resting, or notsignificantly physiologically flexed, position. The view illustrated inFIG. 3 is a view of the artificial hip joint prosthesis in vivo withoutthe surrounding skin, ligaments and other surrounding tissues depicted.An embodiment of an artificial hip joint prosthesis such as illustratedin FIG. 3 can include an acetabular shell, although it is not visible inthe view depicted in FIG. 3.

FIG. 3 shows that the hip joint prosthesis 100 includes a visibleacetabular liner 175 positioned adjacent to the pelvis 160, forming abone-prosthesis interface 120. A particle retaining structure 195 isconnected at a first end to the acetabular liner 175 and to the femoralstem 187 at a second end. The acetabular liner 175 has a plurality offluid deflecting structures 140 attached and configured to deflect jointfluid flow toward the particle retaining structure 195. The fluiddeflecting structures 140 attached to the acetabular liner 175 arepositioned around the circumference of the acetabular liner 175 in aregion of the non-contact surface of the acetabular liner 175. In theview shown in FIG. 3, the hip joint prosthesis 100 is in a restingposition and the synovial fluid flow in the joint is not undersignificant pressure at any particular location. The fluid deflectingstructures 140 attached to the acetabular liner 175 are, therefore,positioned substantially perpendicularly relative to the surface of theacetabular liner 175 facing the interior region of the joint 100. Thefluid deflecting structures 140 attached to the acetabular liner 175 areof a size, shape and material fabrication to not impede motion of thejoint 100, including being predicted to not come into contact with thefemoral head 182 or the femoral stem 187 during routine physiologicalactivity. Similarly, particle retaining structure 195 is configured tonot impede routine joint motion.

FIG. 3 depicts that the hip joint prosthesis 100 includes a femoral head182 and a femoral stem 187. A plurality of fluid deflecting structures145 are attached to the femoral stem 187. The plurality of fluiddeflecting structures 145 attached to the femoral stem 187 arepositioned around the circumference of the femoral stem 187 in a regionof the non-contact surface 135 of the femoral stem 187. The particleretaining structure 195 is affixed to the femoral stem 187 at a positiondistal to the ring formed by the plurality of fluid deflectingstructures 145. The particle retaining structure 195 is affixed to theacetabular liner 175 at a position distal to the ring formed by theplurality of fluid deflecting structures 140. The particle retainingstructure 195 is within the synovial membrane boundary 190 but outsideof the rings formed by the fluid deflecting structures 140, 145. Asnoted above, in the view shown in FIG. 3, the hip joint prosthesis 100is in a resting position and the synovial fluid flow in the joint is notunder significant pressure at any particular location. The fluiddeflecting structures 145 attached to the non-contact surface 135 of thefemoral stem 187 are, therefore, positioned substantiallyperpendicularly relative to the surface of the femoral stem 187 facingthe interior region of the joint 100. Similarly, the fluid deflectingstructures 140 attached to the non-contact surface 130 of the acetabularliner 175 are positioned substantially perpendicularly relative to thesurface of the non-contact surface 130 of the acetabular liner 175. Thefluid deflecting structures 145 attached to the femoral stem 187 are ofa size, shape and material fabrication to not impede motion of the joint100, including being predicted to not come into contact with the femoralhead 182 or the acetabular liner 175 during routine physiologicalactivity.

FIG. 4 depicts a hip joint prosthesis 100 in vivo during physiologicalmovement of the joint 100. The view illustrated in FIG. 4 is an externalview of the joint 100, similar to the view depicted in FIG. 3. Theartificial hip joint prosthesis 100 depicted in FIG. 4 is depicted invivo in a flexed or bent position, similar to the view depicted incross-section in FIG. 2. As illustrated in FIG. 4, the artificial hipjoint prosthesis 100 includes an acetabular liner 175, a femoral head182 and a femoral stem 187. A particle retaining structure 195 isconnected at a first end to the acetabular liner 175 and to the femoralstem 187 at a second end. FIG. 4 depicts the joint during or immediatelyafter moving to a flexed position, which is expected to result in atransient increase in synovial fluid pressure at the bone-prosthesisinterface regions put into closer proximity during the jointrepositioning. For example, FIG. 4 illustrates that regions of thenon-contact surface 130A of the acetabular liner 175 and a region of thenon-contact surface 135A of the femoral stem 187 are being placed incloser proximity due to the joint repositioning (e.g. relative to thejoint position illustrated in FIG. 3). Correspondingly, FIG. 4 showsthat regions of the non-contact surface 130B of the acetabular liner 175and a region of the non-contact surface 135B of the femoral stem 187 aremoved away from each other due to the joint repositioning (e.g. relativeto the joint position illustrated in FIG. 3).

As also described above, for a transient period during and immediatelyafter the joint flexing or bending from the position illustrated in FIG.3 to the position illustrated in FIG. 4, there is an increase insynovial fluid pressure in the region between the non-contact surface130A of the acetabular liner 175 and a region of the non-contact surface135A of the femoral stem 187. This results in an increased synovialfluid flow across the joint, as illustrated by the dotted arrows acrossthe joint 100 in FIG. 4. The joint bending, and the associated localizedsynovial fluid pressure increase, results in the flexing of the fluiddeflecting structures 140A attached to the non-contact surface 130A ofthe acetabular liner 175. The joint bending, and the associatedlocalized synovial fluid pressure increase, also results in the flexingof the fluid deflecting structures 145A attached to the non-contactsurface 135A of the femoral stem 187. As shown in FIG. 4, the fluiddeflecting structures 140B, 145B attached to the non-contact surfaces130B, 135B of the acetabular liner 175 and the femoral stem 187 whichare not subject to increased synovial fluid pressure do not bend or flexin the same manner as the fluid deflecting structures 140A, 145A subjectto the localized synovial fluid pressure increase associated with thejoint bending. The combination of localized synovial fluid pressurechange and diversion of the fluid flow by the fluid deflectingstructures 140, 145 causes fluid flow to be directed towards the innersurface of the particle retaining structure 195. In particular, jointfluid flow is directed towards the inner surface of the particleretaining structure 195 in the region of the particle retainingstructure 195 adjacent to the fluid deflecting structures 140B, 145Bwhich are not subject to increased synovial fluid pressure.

FIG. 5 shows components of an artificial hip joint prosthesis ex-vivo.These components can be included in some embodiments of an artificialhip joint prosthesis, although not all embodiments will include all ofthe components depicted in FIG. 5. FIG. 5 depicts that the artificialhip joint prosthesis includes an acetabular shell 170. The acetabularshell 170 is configured to fit around an acetabular liner 175. Theacetabular liner 175 includes a non-contact surface 130. A plurality offluid deflecting structures 140 are attached to the non-contact surface130 of the acetabular liner 175. The artificial hip joint prosthesisalso includes a femoral head 182 configured to attach to a femoral stem187 through routine means. The femoral head 182 includes a non-contactsurface 500 with a particle retaining structure 510 configured to beattached to the non-contact surface 500. The particle retainingstructure 510 shown in FIG. 5 is configured as a substantially planarstructure, including a surface configured to mate with the non-contactsurface 500 of the femoral head 182. The femoral stem 187 includes anon-contact surface 135 with a plurality of attached fluid deflectingstructures 145. The non-contact surfaces 130, 500, 135 depicted in FIG.5 are each predicted to not come into direct contact with the adjacentsurfaces of the artificial hip joint prosthesis during routinephysiological use of the hip joint in vivo.

The fluid deflecting structures 140, 145 shown in FIG. 5 are depicted assubstantially linear, or ciliated, structures. The dimensions ofsubstantially linear fluid deflecting structures 140, 145, such asheight and diameter, would depend on the particular embodiment. Thesubstantially linear fluid deflecting structures 140, 145 are configuredto direct fluid flow through the joint towards the particle retainingstructure 510 attached to the non-contact surface 500 of the femoralhead 182. The particle retaining structure 510 sequesters and removesparticles from the fluid flow. For example, the particle retainingstructure 510 can be fabricated as a foam structure including along-lasting adhesive on its surface, the adhesive configured to adhereparticulates from the fluid flow in vivo. The substantially linear fluiddeflecting structures 140, 145 are constructed of a size, shape andmaterial to not impede routine physiological use of the associated hipjoint in vivo while still providing fluid deflection during joint motion(e.g. as described relative to FIGS. 2 and 4, above). Thus, thepositioning and number of the substantially linear fluid deflectingstructures 140, 145 on the non-contact surfaces 130, 500, 135 willdepend on the specific embodiment. Factors to consider in the size,shape, positioning, number and material of the substantially linearfluid deflecting structures 140, 145 on the non-contact surfaces 130,135 in various embodiments include the total size of the hip joint invivo, the relative size of the hip joint components 170, 175, 182, 187,and the expected fluid pressures within the hip joint in vivo.

FIG. 6 illustrates aspects of some embodiments of a femoral stem 187with attached fluid deflecting structures 145 on a non-contact surface135. As illustrated in FIG. 6, in some embodiments of a hip jointprosthesis, a non-contact surface 135 includes a plurality of deflectingstructures 145 attached to project at an angle from the non-contactsurface 135. The plurality of deflecting structures 145 are eachattached to a band 600 at their terminal end closest to the non-contactsurface 135. The band 600 is configured to secure each of the pluralityof deflecting structures 145 in position relative to the non-contactsurface 135. The band 600 illustrated in FIG. 5 is shown as a single,unified, smooth band, but in some embodiments the band 600 can includemultiple components, grooves or tabs configured to stabilize the band600 relative to the non-contact surface 135. The band 600 is alsostabilized relative to the non-contact surface 135 through placement ina groove 610 of the non-contact surface 135. The groove 610 of thenon-contact surface 135 can have a single, substantially smooth surface,as shown in FIG. 6. In some embodiments, the groove 610 can includemultiple channels or surfaces. For example, in some embodiments a groove610 can include edge structures configured to mate with correspondingtab structures of a band 600 to functionally stabilize the band 600relative to the non-contact surface 135. Although a band 600 andcorresponding groove 610 are illustrated in FIG. 6 relative to a femoralstem 187, some embodiments include a band 600 and corresponding groove610 on other components of an artificial joint, e.g. an acetabular cup.Although the band 600 and corresponding groove 610 are shown in FIG. 6relative to an artificial hip joint prosthesis, some embodiments includeone or more bands 600 with attached fluid deflecting structures 145 andcorresponding grooves 610 on other types of artificial joints, e.g. anartificial knee or shoulder.

FIG. 7A shows aspects of a femoral stem 187 including a plurality offluid deflecting structures 145 on a non-contact surface 135. A portionof the femoral stem 187 including the non-contact surface 135 is shownin an enlarged view in FIG. 7B to illustrate aspects of the attachmentof the fluid deflecting structures 145 to the non-contact surface 135.The non-contact surface 135 includes a series of apertures 700, witheach of the plurality of fluid deflecting structures 145 projectingthrough a single aperture 700.

As illustrated in FIG. 7B, a region of a fluid deflecting structure 145traverses through a single aperture 700. Each of the apertures 700 ispositioned between the external non-contact surface 135 and a cavity 710in the femoral stem 187. Each cavity 710 is of a size and shape that islarger, e.g. wider and/or longer, than the size of the adjacent aperture700. Each of the fluid deflecting structures 145 includes a projection720 at an end of the fluid deflecting structure 145 configured to fitwithin the cavity 710. The size and the shape of the projection 720corresponds with the size and shape of the associated cavity 710 in amanner predicted to stabilize the fluid deflecting structure 145 withinthe cavity 710 and associated aperture 700. The size and shape of thecavity 710 can, for example, position the end of the fluid deflectingstructure 145 with the projection at a particular angle relative to thenon-contact surface 135. The size and shape of the cavity 710 can, forexample, fix the end of the fluid deflecting structure 145 with theprojection relative to the non-contact surface 135. The size and shapeof the cavity 710 can, for example, include sufficient space to allowfor some motion of the end of the fluid deflecting structure 145 withthe projection relative to the non-contact surface 135. Althoughapertures 700, cavities 710 and corresponding projections 720 from thefluid deflecting structures 145 are illustrated in FIG. 7 relative to afemoral stem 187, some embodiments include apertures 700, cavities 710and corresponding projections 720 associated with the fluid deflectingstructures attached to non-contact regions on other components of anartificial joint, e.g. an acetabular cup or femoral head component.Although the apertures 700, cavities 710 and corresponding projections720 from the fluid deflecting structures 145 are shown in FIGS. 7A and7B relative to an artificial hip joint prosthesis, some embodimentsinclude one or more apertures 700, cavities 710 and correspondingprojections 720 from the fluid deflecting structures 145 on other typesof artificial joints, e.g. an artificial knee or shoulder.

FIG. 8 illustrates aspects of an artificial knee joint 800 prosthesis invivo for a left knee. The artificial knee joint 800 prosthesisillustrated in FIG. 8 is shown in a frontal view, with the surroundingskin, ligaments, and tissues removed for clarity of presentation. Theartificial knee joint 800 shown in FIG. 8 includes components 830, 810attached to both the femur 813 and the tibia 823. A synovial membraneborder 840 is shown as a dotted line to roughly define the edge of thesynovial fluid region of the artificial knee joint 800. In someembodiments, an artificial knee joint 800 prosthesis will be partial,i.e. not include all of the components illustrated in FIG. 8.

FIG. 8 shows a femur 813 including an attached femoral component 810 ofan artificial knee joint 800 prosthesis. The femoral component 810includes a bone-facing surface, which is positioned relative to thefemur 813 in vivo to create a bone-prosthesis interface 817. The femoralcomponent 810 also includes a non-contact region including a non-contactsurface 862. The non-contact surface 862 is a surface of the femoralcomponent 810 that is predicted to not come into contact with othercomponents of the artificial knee joint 800, for example the tibialspacer 820 or the tibial component 830, during normal physiological useof the artificial knee joint 800.

The artificial knee joint 800 shown in FIG. 8 also includes a tibialcomponent 830 with a bone-facing surface attached to the tibia 823 invivo to form a bone-prosthesis interface 827. The tibial component 830is attached to a tibial spacer 820. In the embodiment illustrated inFIG. 8, the tibial spacer 820 includes a non-contact region including anon-contact surface 864. The non-contact surface 864 is a surface of thetibial spacer 820 that is predicted to not come into contact with othercomponents of the artificial knee joint 800, for example the femoralcomponent 810, during normal physiological use of the artificial kneejoint 800.

A plurality of fluid deflecting structures 854 are attached to theperiphery of the non-contact surface 864 of the tibial spacer 820.Although not shown in FIG. 8, some embodiments include one or more fluiddeflecting structures attached to a non-contact surface of the tibialcomponent 830. A plurality of fluid deflecting structures 852 areattached to the periphery of the non-contact surface 862 of the femoralcomponent 810. A medial particle retaining structure 195A is connectedat a first end to the femoral component 810 and to the tibial spacer 820at a second end. A lateral particle retaining structure 195B isconnected at a first end to the femoral component 810 and to the tibialspacer 820 at a second end. The particle retaining structures 195A, 195Bare shown in a cross section view. The fluid deflecting structures 852,854 are positioned, spaced and shaped to divert the fluid flow withinthe joint away from the bone-prosthesis interfaces 817, 827. The fluiddeflecting structures 852, 854 are positioned, spaced and shaped todivert the fluid flow within the joint away toward the particleretaining structures 195A, 195B.

As shown in FIG. 8, in some embodiments the fluid deflecting structures852, 854 can be formed as substantially flat rectangular structures withrounded edges. In some embodiments, the fluid deflecting structures 852can be formed as flanges or linear structures. The fluid deflectingstructures 852, 854 can be attached to the associated components, i.e.the femoral component 810, the tibial spacer 820 and the tibialcomponent 830 with structures suitable for a particular embodiment. Forexample, the fluid deflecting structures 852, 854 can be attached to theassociated components through attachment to bands inserted intocorresponding grooves in the components (e.g. as shown in FIG. 6). Forexample, the fluid deflecting structures 852, 854 can be attached to theassociated components through stabilization in cavities in thecomponents (e.g. as shown in FIG. 7). For example, the fluid deflectingstructures 852, 854 can be attached to the associated components throughadhesive, epoxy or glue. For example, the fluid deflecting structures852, 854 can be fabricated as part of the components, for exampleintegral to a component fabricated from a plastic material such aspolyethylene.

As FIG. 8 illustrates, in some embodiments an artificial knee joint 800prosthesis includes: a bone-facing surface of a knee joint prosthesis,the bone-facing surface configured to face a bone-prosthesis interface817, 827 in vivo; a non-contact surface 862, 864 of the knee jointprosthesis, the non-contact surface 862, 864 adjacent to the bone-facingsurface of the knee joint prosthesis; at least one fluid deflectionstructure 852, 854 positioned on the non-contact surface 862, 864, thefluid deflection structure 852, 854 positioned to deflect synovial fluidaway from the bone-prosthesis interface 817, 827 in vivo; and at leastone particle retaining structure 195A, 195B positioned to contact thedirected flow of synovial fluid and configured to retain particlespresent within the synovial fluid. In some embodiments, the bone-facingsurface of the artificial knee joint 800 prosthesis includes one or moreof: a bone-facing surface of a tibial spacer component of the knee jointprosthesis, a bone-facing surface of a tibial component of the kneejoint prosthesis, a bone-facing surface of a femoral component of theknee joint prosthesis, or a bone-facing surface of a patellar componentof the knee joint prosthesis. In some embodiments, the non-contactsurface 862, 864 of the knee joint prosthesis includes one or more of: aedge region 864 of a liner of a tibial spacer component 820 of the kneejoint prosthesis; a edge region 862 of a tibial component 830 of theknee joint prosthesis; and a edge region of a patellar component of theknee joint prosthesis (not shown in FIG. 8).

FIG. 9 shows a view of an embodiment similar to that shown in FIG. 8,from a side-facing or medial view of the left knee relative to theindividual. The embodiment illustrated in FIG. 9 is shown in a sideview, with the surrounding skin, ligaments and tissues removed forclarity of presentation. The artificial knee joint 800 shown in FIG. 9includes components 830, 810 attached to both the femur 813 and thetibia 823. A patella is not depicted, although some embodiments includean artificial patella that is part of the artificial knee joint 800.

As shown in FIG. 9, the femur 813 has an attached femoral component 810.The femoral component 810 includes a region with a non-contact surface862. Attached to the non-contact surface 862 of the femoral component810 are a series of fluid deflecting structures 852. FIG. 9 also showsthat a tibial component 830 in combination with a tibial spacer 820 ofthe artificial knee joint 800 are attached to the tibia 823. The tibialcomponent 830 has a bone-facing surface configured to form abone-implant interface 827 in vivo. The tibial spacer 820 includes aregion with a non-contact surface 864. Attached to the non-contactsurface 864 of the tibial spacer 820 are a series of fluid deflectingstructures 854. At the medial edge of the knee joint, a particleretaining structure 195A is attached at a first edge region 900 to thefemoral component 810 and at a second edge region 910 to the tibialspacer 820. In the illustrated embodiment, there are no fluid deflectingstructures 852, 854 attached to the medial region of either non-contactsurface 862 of the femoral component 810 or the non-contact surface 864of the tibial spacer 820 in order to retain space for the particleretaining structure 195A. Although not shown in FIG. 9, in someembodiments there is a similar particle retaining structure attached tothe lateral side of the artificial knee joint 800 (e.g. see FIG. 8).

The fluid deflecting structures 852, 854 are configured, in size shapeand position, to reduce synovial fluid flow at the bone-implantinterfaces 817, 827 in vivo. The fluid deflecting structures 852, 854are configured to reduce synovial fluid pressure at the bone-implantinterfaces 817, 827 in vivo during physiological use of the knee joint.The fluid deflecting structures 852, 854 are configured, in size shapeand position, to divert joint fluid flow towards the particle retainingstructure 195A. The exact placement, size, shape and positioning of thefluid deflecting structures 852, 854 attached to an artificial kneejoint 800 prosthesis will vary depending on the embodiment. For example,the size, shape, positioning, placement and fabrication of the fluiddeflecting structures 852, 854 will vary depending on the expectedsynovial fluid flow during physiological movement in vivo and the sizeand shape of the artificial knee joint 800. The particular fluiddeflecting structures 852, 854 for an embodiment will be configured tomitigate synovial fluid flow rates at the bone-implant interfaces 817,827 in vivo. The particular fluid deflecting structures 852, 854 for anembodiment will be configured to reduce transient synovial fluidpressure at the bone-implant interfaces 817, 827 during physiologicaluse in vivo. The particular fluid deflecting structures 852, 854 for anembodiment will be configured to divert joint fluid flow in thedirection of the inner surface of the particle retaining structure 195A.

As shown in situ in FIGS. 8 and 9, a knee joint prosthesis includes: atleast one bone-facing surface of a knee joint prosthesis, thebone-facing surface configured to face a bone-prosthesis interface 817,827 in vivo; a non-contact surface 862, 864 of the knee jointprosthesis, the non-contact surface 862, 864 adjacent to the bone-facingsurface 817, 827 of the knee joint prosthesis; at least one fluiddeflection structure 852, 854 positioned on the non-contact surface 862,864, the fluid deflection structure 852, 854 positioned to deflectsynovial fluid away from the bone-prosthesis interface 817, 827 in vivo;and at least one particle retaining structure positioned to contact thedirected flow of synovial fluid and configured to retain particlespresent within the synovial fluid. In some embodiments, the bone-facingsurface of the knee joint prosthesis includes a bone-facing surface of atibial spacer 820 component of the knee joint prosthesis. In someembodiments, the bone-facing surface of the knee joint prosthesisincludes a bone-facing surface of a tibial component 830 of the kneejoint prosthesis. In some embodiments, the bone-facing surface of theknee joint prosthesis includes bone-facing surface of a femoralcomponent 810 of the knee joint prosthesis. In some embodiments, thebone-facing surface of the knee joint prosthesis includes bone-facingsurface of a patellar component of the knee joint prosthesis.

A knee joint prosthesis includes at least one non-contact surface 862,864. The non-contact surface 862, 864 is a surface of the knee jointprosthesis in a region that is not expected to come in contact withanother surface of a different region of the knee joint prosthesisduring normal physiological movement of the knee joint in vivo. Some ofthe non-contact surfaces 862, 864 of a knee joint prosthesis areattached to at least one fluid deflection structure 852, 854. A fluiddeflection structure can be of a variety of sizes and shapes, configuredto mitigate synovial fluid flow rate and fluid pressure at thebone-prosthesis interface during physiological use of the prosthesis invivo. A fluid deflection structure is configured to mitigate synovialfluid flow rate and fluid pressure at the bone-prosthesis interfacewithout impeding joint movement.

In some embodiments, a fluid deflection structure positioned on anon-contact surface of the an artificial knee joint prosthesis isconfigured as at least one flange structure positioned to extend fromthe non-contact surface. For example, a flange structure can beconfigured as a projecting rim or collar from the non-contact surface.For example, a flange structure can be configured as one or more ridgesattached to the non-contact surface. Some embodiments include at leastone flange structure positioned to extend from the non-contact surfaceat an angle substantially between 10 degrees and 80 degrees of a planeestablished by the contact surface and relative to the bone-facingsurface of the knee joint prosthesis. Some embodiments include at leastone flange structure positioned to extend from the non-contact surfaceat an angle substantially between 100 degrees and 170 degrees of a planeestablished by the contact surface and relative to the bone-facingsurface of the knee joint prosthesis. Some embodiments include at leastone flange structure positioned to extend from the non-contact surfaceat a substantially right angle from a plane established by the contactsurface and relative to the bone-facing surface of the knee jointprosthesis. Some embodiments include at least one flange structure witha first end connected to the non-contact surface and a second end distalto the non-contact surface, wherein the flange structure is widest atthe first end and narrowest at the second end. Some embodiments includeat least one flange structure with a first end connected to thenon-contact surface and a second end distal to the non-contact surface,wherein the flange structure tapers from a widest point at the first endto a narrow point at the second end. Some embodiments include at leastone flange structure with a curvilinear structure.

As illustrated in FIGS. 8 and 9, a fluid deflection structure 852, 854positioned on a non-contact surface 862, 864 can include at least onefluid deflection structure with a first end connected to the non-contactsurface and a second end distal to the non-contact surface. Also asshown in FIGS. 8 and 9, in some embodiments a fluid deflection structure852, 854 positioned on a non-contact surface 862, 864 can include aplurality of fluid deflection structures. Some embodiments include oneor more substantially curved fluid deflection structures. Someembodiments include one or more substantially straight fluid deflectionstructures.

One or more fluid deflection structures positioned on a non-contactsurface 862, 864 can include a plurality of linear projections. Thelinear projections can be ciliated or hair-like projections. Someembodiments include a plurality of linear projections positioned toextend from the non-contact surface at an angle substantially between 10degrees and 80 degrees of a plane established by the contact surface andrelative to the bone-facing surface of the knee joint prosthesis. Someembodiments include a plurality of linear projections positioned toextend from the non-contact surface at an angle substantially between100 degrees and 170 degrees of a plane established by the contactsurface and relative to the bone-facing surface of the knee jointprosthesis. Some embodiments include a plurality of linear projectionspositioned to extend from the non-contact surface at a substantiallyright angle from a plane established by the contact surface and relativeto the bone-facing surface of the knee joint prosthesis.

A fluid deflection structure attached to a non-contact surface in agiven embodiment is configured to deflect synovial fluid flow away froma bone-prosthesis interface and toward a particle retaining structure,as well as to mitigate transient fluid pressure at a bone-prosthesisinterface during use of the joint in vivo. A fluid deflection structurecan be attached to a non-contact surface of a knee joint prosthesis by avariety of means, depending on the expected duration and physiologicalpressures of use in vivo. For example, a fluid deflection structure canbe attached to the non-contact surface of a knee joint prosthesis withan adhesive, epoxy or glue. For example, a fluid deflection structurecan be attached to a band or similar structure stabilized relative tothe non-contact surface of a knee joint prosthesis (see, e.g. FIG. 6).For example, a fluid deflection structure can include an end that isstabilized within a cavity of the non-contact surface of a knee jointprosthesis (see, e.g. FIG. 7).

The fabrication of a fluid deflection structure attached to anon-contact surface of a knee joint prosthesis can be in a variety ofmaterials, depending on the embodiment. For example, a fluid deflectionstructure should be fabricated from a material suitable to attach to theassociated non-contact surface. For example, a fluid deflectionstructure should be fabricated from a material suitable for implantationwith a knee joint prosthesis in vivo, including durability over theexpected dynamic use and duration of the knee joint prosthesis. Thematerial(s) used to fabricate a fluid deflection structure attached to anon-contact surface of a knee joint prosthesis can be substantiallyrigid at physiological conditions when the artificial joint is utilizedin vivo. The material(s) used to fabricate a fluid deflection structureattached to a non-contact surface of a knee joint prosthesis can beflexible at physiological conditions when the artificial joint isutilized in vivo. For example, a fluid deflection structure positionedon a non-contact surface of a knee joint prosthesis can be configured toflex to a degree sufficient to permit a larger synovial fluid flow rateaway from the bone-prosthesis interface during periods of increasedsynovial fluid pressure in the region of the non-contact surface whenthe artificial joint is utilized in vivo at physiological conditions,and to permit a smaller synovial fluid flow rate away from thebone-prosthesis interface during periods of reduced synovial fluidpressure when the artificial joint is utilized in vivo at physiologicalconditions. For example, a fluid deflection structure positioned on anon-contact surface of a knee joint prosthesis can be configured to flexto a degree sufficient to permit an increased synovial fluid flow rateaway from the bone-prosthesis interface in response to increased fluidpressure in a region adjacent to the bone-prosthesis interface.

As shown in FIG. 9, in some embodiments at least one particle retainingstructure is configured as a substantially planar structure. In someembodiments, at least one particle retaining structure includes amesh-like structure. For example, a mesh-like structure can includeapertures of an appropriate size range to sequester particles from thefluid flow (e.g. apertures in the 0.05 to 0.01 mm range). In someembodiments, at least one particle retaining structure includes a filterstructure. In some embodiments, at least one particle retainingstructure includes a foam structure. For example, a particle retainingstructure such as that illustrated in FIG. 9 can be fabricated from asubstantially planar foam structure. Some embodiments include at leastone particle retaining structure configured as a group of projections,each of the projections positioned to contact the flow of synovial fluidand configured to retain particles present within the synovial fluid.For example, the projections can be configured with a size, shape,flexibility and positioning to contact the flow of synovial fluid. Theprojections can also include a surface coating configured to retainparticulate structures from the fluid flow, for example a surfacecoating including antibodies configured to bind proteins on the surfaceof the particles. In some embodiments, at least one particle retainingstructure includes a hydrophobic surface. In some embodiments, at leastone particle retaining structure includes a structure configured toretain non-physiological particles present in the synovial fluid, forexample a chemical configured to bind to non-physiological materials(e.g. plastic or ceramic). In some embodiments, at least one particleretaining structure includes a structure configured to retain particlesincluding artificial materials, for example a magnet configured to bindferromagnetic particles.

In some embodiments, as illustrated in FIGS. 8 and 9, a knee jointprosthesis includes two or more components, each of which include anon-contact surface in at least one region of the component, and each ofwhich include one or more fluid deflecting structures attached to therespective non-contact surface. For example, a knee joint prosthesis caninclude: at least one femoral component, wherein the femoral componentincludes at least one fluid deflection structure positioned on thenon-contact surface; and at least one tibial component, wherein thetibial component includes at least one fluid deflection structurepositioned on the non-contact surface. In some embodiments, a knee jointprosthesis includes at least two components, a first component whichincludes at least one fluid deflection structure affixed to anon-contact surface, and a second component which includes at least oneparticle retaining structure affixed to a surface.

Some embodiments include a shoulder joint prosthesis including: abone-facing surface of a shoulder joint prosthesis, the bone-facingsurface configured to face a bone-prosthesis interface in vivo; anon-contact surface of the shoulder joint prosthesis, the non-contactsurface adjacent to the bone-facing surface of the shoulder jointprosthesis; at least one fluid deflection structure positioned on thenon-contact surface, the fluid deflection structure positioned todeflect synovial fluid away from the bone-prosthesis interface in vivo;and at least one particle retaining structure positioned to contact thedirected flow of synovial fluid and configured to retain particlespresent within the synovial fluid.

For example, FIG. 10 illustrates a shoulder joint prosthesis 1000 invivo, including a humerus bone 1010 with an attached humerus spacer 1013and humerus cap 1017 of the prosthesis. There is a humerusbone-prosthesis interface 1043 between the humerus bone 1010 and thehumerus spacer 1013. The shoulder joint prosthesis 1000 shown in FIG. 10also includes a glenoid component 1023 attached to a glenoid cavity 1020of the scapula bone. The embodiment illustrated in FIG. 10 is aconventional shoulder joint prosthesis, however some embodiments includea shoulder joint prosthesis that is a reverse shoulder joint prosthesis.

Each of the individual components 1013, 1017, 1023 of the shoulder jointprosthesis 1000 shown in FIG. 10 includes a bone-facing surface. Thebone-facing surfaces of the components 1013, 1017, 1023 are not visiblein FIG. 10 as the shoulder joint prosthesis 1000 is illustrated in vivo,with the bone-facing surfaces obscured by the bone-prosthesis interfacesand the prosthesis-prosthesis interfaces. There is a scapulabone-prosthesis interface 1053 between the glenoid component 1023 of theprosthesis and the glenoid cavity 1020 of the scapula bone, with theregion of the glenoid component 1023 facing the glenoid cavity 1020 ofthe scapula bone forming a bone-facing surface. There is abone-prosthesis interface 1043 between the humerus 1010 and the humerusspacer 1013, with the region of the humerus spacer 1013 facing thehumerus 1010 forming a bone-facing surface. There is aprosthesis-prosthesis interface between the humerus cap 1017 and thehumerus spacer 1013, with a region of the humerus cap 1017 forming abone-facing surface. The bone-facing surface of the humerus cap 1017does not contact the bone, however it faces the humerus 1010 and thusforms a bone-facing surface. In some embodiments, the bone-facingsurface of the shoulder joint prosthesis includes a bone-facing surfaceof a liner of a glenoid component of the shoulder joint prosthesis. Insome embodiments, the bone-facing surface of the shoulder jointprosthesis includes a bone-facing surface of a glenoid fixationcomponent of the shoulder joint prosthesis. In some embodiments, thebone-facing surface of the shoulder joint prosthesis includes abone-facing surface of a humeral head component of the shoulder jointprosthesis. In some embodiments, the bone-facing surface of the shoulderjoint prosthesis includes a bone-facing surface of a stem of a humeralcomponent of the shoulder joint prosthesis.

A non-contact surface 1040, 1050 of a shoulder joint prosthesis 1000 isa surface of a region of the shoulder joint prosthesis 1000 that ispredicted to not come into contact with another component of theshoulder joint during normal physiological movement of the joint. Asshown in FIG. 10, the humerus spacer 1013 has a non-contact surface 1040around the edge surrounding the bone-prosthesis interface 1043. Someembodiments of a shoulder joint prosthesis include a non-contact surfacethat is a edge region of a humeral head component of the shoulder jointprosthesis. Some embodiments of a shoulder joint prosthesis include anon-contact surface that is a edge region of a stem of a humeralcomponent of the shoulder joint prosthesis. The glenoid component 1023also has a non-contact surface 1050 surrounding the edge of the glenoidcomponent 1023 adjacent to the scapula bone-prosthesis interface 1053.Some embodiments of a shoulder joint prosthesis include a non-contactsurface that is a edge region of a glenoid component of the shoulderjoint prosthesis. Some embodiments of a shoulder joint prosthesisinclude a non-contact surface that is a edge region of a glenoidfixation component of the shoulder joint prosthesis.

The shoulder joint prosthesis 1000 shown in FIG. 10 includes a pluralityof fluid deflecting structures 1047 attached to the non-contact surface1040 of the humerus spacer 1013. The shoulder joint prosthesis 1000shown in FIG. 10 also includes a plurality of fluid deflectingstructures 1057 attached to the non-contact surface 1050 surrounding theedge of the glenoid component 1023. A fluid deflection structure 1047,1057 of a shoulder joint prosthesis 1000 is a structure attached to anon-contact surface 1040, 1050 and configured to mitigate fluid flowaway from a bone-prosthesis interface 1043, 1053 and toward a particleretaining structure 1030 as well as to reduce transient fluid pressureat a bone-prosthesis interface 1043, 1053 during physiological use ofthe shoulder joint in vivo. A fluid deflecting structure can be attachedto a non-contact surface of a shoulder joint prosthesis by a variety ofmeans, depending on the embodiment. For example, a fluid deflectingstructure can be attached to a non-contact surface of a shoulder jointprosthesis by glue, adhesive or epoxy. For example, a fluid deflectingstructure can be attached to a band, which is then stabilized in agroove in a non-contact surface of a shoulder joint prosthesis (see FIG.6). For example, a fluid deflecting structure can include a end regionconfigured to stabilize the fluid deflecting structure within a cavityin a prosthesis component (see FIG. 7).

In some embodiments, the at least one fluid deflection structurepositioned on the non-contact surface includes at least one flangestructure positioned to extend from the non-contact surface. Forexample, in some embodiments the at least one flange structure ispositioned to extend from the non-contact surface at an anglesubstantially between 10 degrees and 80 degrees of a plane establishedby the contact surface and relative to the bone-facing surface of theshoulder joint prosthesis. Some embodiments include at least one flangestructure positioned to extend from the non-contact surface at an anglesubstantially between 100 degrees and 170 degrees of a plane establishedby the contact surface and relative to the bone-facing surface of theshoulder joint prosthesis. Some embodiments include at least one flangestructure positioned to extend from the non-contact surface at asubstantially right angle from a plane established by the contactsurface and relative to the bone-facing surface of the shoulder jointprosthesis. A flange structure can include at least one flange structurewith a first end connected to the non-contact surface and a second enddistal to the non-contact surface, wherein the flange structure iswidest at the first end and narrowest at the second end. A flangestructure can include at least one flange structure with a first endconnected to the non-contact surface and a second end distal to thenon-contact surface, wherein the flange structure tapers from a widestpoint at the first end to a narrow point at the second end. A flangestructure can include at least one flange structure with a curvilinearstructure. A flange structure can include at least one flange structurewith a substantially straight structure.

As shown in FIG. 10, in some embodiments a shoulder joint prosthesis1000 includes at least one fluid deflection structure 1047, 1057 with afirst end connected to the non-contact surface and a second end distalto the non-contact surface. Also as shown in FIG. 10, some embodimentsinclude a plurality of fluid deflection structures attached to one ormore non-contact surfaces. For example, some embodiments include atleast one scapular component, wherein the scapular component includes atleast one fluid deflection structure positioned on the non-contactsurface, and at least one humeral component, wherein the humeralcomponent includes at least one fluid deflection structure positioned onthe non-contact surface. Some embodiments include a single fluiddeflection structure, for example a fluid deflection structureencircling the edge of a non-contact surface.

In some embodiments, a shoulder joint prosthesis 1000 includes at leastone fluid deflection structure including a plurality of linearprojections. For example, the plurality of linear projections can beshaped as rods or cilia, for example as hair-like projections. See, e.g.FIG. 5. Fluid deflection structures configured as linear projections canbe positioned to extend from the non-contact surface at an anglesubstantially between 10 degrees and 80 degrees of a plane establishedby the contact surface and relative to the bone-facing surface of theshoulder joint prosthesis. Fluid deflection structures configured aslinear projections can be positioned to extend from the non-contactsurface at an angle substantially between 100 degrees and 170 degrees ofa plane established by the contact surface and relative to thebone-facing surface of the shoulder joint prosthesis. Fluid deflectionstructures configured as linear projections can be positioned to extendfrom the non-contact surface at an substantially right angle from aplane established by the contact surface and relative to the bone-facingsurface of the shoulder joint prosthesis.

Depending on the embodiment, a fluid deflection structure attached to anon-contact surface of a shoulder joint prosthesis can be configured ina variety of forms to mitigate synovial fluid flow and pressure at thebone-prosthesis interface, as well as to divert fluid flow toward theparticle retaining structure 1030. The specific size, shape andconfiguration of a fluid deflection structure depends on the embodiment,including the size, shape, and expected physiological stresses on ashoulder joint during routine use. Some embodiments include at least onefluid deflection structure positioned on the non-contact surface whereinthe at least one fluid deflection structure is configured as asubstantially straight fluid deflection structure. Some embodimentsinclude at least one fluid deflection structure positioned on thenon-contact surface wherein the at least one fluid deflection structureis configured as a substantially curved fluid deflection structure. Insome embodiments, at least one fluid deflection structure positioned ona non-contact surface of an artificial shoulder joint prosthesis isconfigured to be flexible at physiological conditions when theartificial joint is utilized in vivo. In some embodiments, at least onefluid deflection structure positioned on a non-contact surface of anartificial shoulder joint prosthesis is configured to flex to a degreesufficient to permit a larger synovial fluid flow rate away from thebone-prosthesis interface during periods of increased synovial fluidpressure in the region of the non-contact surface when the artificialjoint is utilized in vivo at physiological conditions, and to permit asmaller synovial fluid flow rate away from the bone-prosthesis interfaceduring periods of reduced synovial fluid pressure when the artificialjoint is utilized in vivo at physiological conditions. In someembodiments, at least one fluid deflection structure positioned on anon-contact surface of an artificial shoulder joint is configured toflex to a degree sufficient to permit an increased synovial fluid flowrate away from the bone-prosthesis interface in response to increasedfluid pressure in a region adjacent to the bone-prosthesis interface.

FIG. 10 illustrates a particle retaining structure 1030 as abubble-shaped membrane 1030 surrounding the joint 1000. The particleretaining structure 1030 includes a first edge attached to thenon-contact surface 1040 of the humeral spacer 1013 and a second edgeattached to the non-contact surface 1050 of the glenoid component 1023.The particle retaining structure 1030 includes a first end, the firstend affixed to the shoulder joint prosthesis; and a second end, thesecond end affixed to an additional component of the shoulder jointprosthesis. The particle retaining structure 1030 is attached with bothedges distal to the fluid deflection structures 1047, 1057 attached tothe joint components, and configured to not interfere with the fluiddeflection structures 1047, 1057 or the normal motion of the joint 1000.A particle retaining structure 1030 such as illustrated in FIG. 10 canbe, for example, configured as a mesh-like structure. A mesh-likestructure can include apertures of a size and shape to retainparticulates of a size and shape range, and to otherwise allow the flowof fluid through the mesh. For example, a mesh-like structure caninclude apertures in the 0.05 to 0.01 mm range.

In some embodiments, a particle retaining structure within a prostheticshoulder joint 1000 can include a substantially planar structure. Forexample, a particle retaining structure with a substantially planarstructure can be shaped as a sheet or ribbon structure around the distaledge of a non-contact region. In some embodiments, a particle retainingstructure within a prosthetic shoulder joint 1000 can include a filterstructure. In some embodiments, a particle retaining structure within aprosthetic shoulder joint 1000 can include a foam structure. In someembodiments, a particle retaining structure within a prosthetic shoulderjoint 1000 can include a group of projections, each of the projectionspositioned to contact the flow of synovial fluid and configured toretain particles present within the synovial fluid.

The particle retaining structure within a prosthetic shoulder joint 1000can be configured in different ways with the goal of binding asequestering particles present in the synovial joint fluid. For example,in some embodiments, a particle retaining structure includes at leastone specialized surface configured to bind to one or more surfaceelements of a particle. For example, in some embodiments, a particleretaining structure includes a hydrophobic surface. For example, in someembodiments, a particle retaining structure includes at least oneantibody affixed to a surface of the particle retaining structure. Forexample, in some embodiments, a particle retaining structure includes astructure configured to retain non-physiological particles present inthe synovial fluid. For example, a particle retaining structure caninclude a magnet configured to bind to ferromagnetic particles in thefluid. For example, in some embodiments, a particle retaining structureincludes a structure configured to retain particles including artificialmaterials. For example, a particle retaining structure can include asurface coating configured to bind artificial materials (e.g. plasticsor ceramics).

Some prosthetic shoulder joints include at least two components, each ofwhich include at least one fluid deflection structure positioned on anon-contact surface. Some prosthetic shoulder joints include at leasttwo components: a first component which includes at least one fluiddeflection structure affixed to a non-contact surface; and a secondcomponent which includes at least one particle retaining structureaffixed to a surface.

One skilled in the art will recognize that the herein describedcomponents (e.g., operations), devices, objects, and the discussionaccompanying them are used as examples for the sake of conceptualclarity and that various configuration modifications are contemplated.Consequently, as used herein, the specific exemplars set forth and theaccompanying discussion are intended to be representative of their moregeneral classes. In general, use of any specific exemplar is intended tobe representative of its class, and the non-inclusion of specificcomponents, devices, and objects should not be taken limiting.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations are not expressly set forth herein for sakeof clarity.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely exemplary, and that in fact many other architectures may beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected”, or“operably coupled,” to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable,” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents. In some instances, one or more components may be similarlyreferred to herein as “configured to,” “configured by,” “configurableto,” “operable/operative to,” “adapted/adaptable,” “able to,”“conformable/conformed to,” etc.

This application may make reference to one or more trademarks, e.g., aword, letter, symbol, or device adopted by one manufacturer or merchantand used to identify and/or distinguish his or her product from those ofothers. Trademark names used herein are set forth in such language thatmakes clear their identity, that distinguishes them from commondescriptive nouns, that have fixed and definite meanings, or, in many ifnot all cases, are accompanied by other specific identification usingterms not covered by trademark. In addition, trademark names used hereinhave meanings that are well-known and defined in the literature, or donot refer to products or compounds for which knowledge of one or moretrade secrets is required in order to divine their meaning. Alltrademarks referenced in this application are the property of theirrespective owners, and the appearance of one or more trademarks in thisapplication does not diminish or otherwise adversely affect the validityof the one or more trademarks. All trademarks, registered orunregistered, that appear in this application are assumed to include aproper trademark symbol, e.g., the circle R or bracketed capitalization(e.g., [trademark name]), even when such trademark symbol does notexplicitly appear next to the trademark. To the extent a trademark isused in a descriptive manner to refer to a product or process, thattrademark should be interpreted to represent the corresponding productor process as of the date of the filing of this patent application.

EXAMPLES Example 1 An Artificial Hip Joint Including Fluid DeflectorStructures Configured to Divert and Diffuse Synovial Fluid Flow

A hip joint prosthesis is fabricated with fluid deflector structures onselect non-contact surfaces of the device. The fluid deflectorstructures are designed to divert joint fluids away from interfacesbetween the artificial device and the patient's bone, and to reduce thevelocity of fluid flow in the artificial joint, thereby reducing thelikelihood of aseptic loosening of the prosthetic implant. The fluiddeflector structures are also configured to minimally impede jointfunction and mobility in vivo. The hip joint prosthesis includes afemoral component which includes a head (or ball), a neck attached tothe head, and a stem which is configured to be implanted in themedullary canal of the femur. See, e.g. FIG. 1. The hip joint prosthesisalso includes an acetabular component which forms a socket. The socketof the acetabular component includes an outer and inner cup, with theouter cup configured to be attached to pelvic bone and the inner cupconfigured to bear the head of the femoral component. See, e.g. FIGS. 1and 2.

The neck and stem of the femoral component are made from titanium (seee.g., U.S. Pat. No. 6,761,741, “Prosthetic Joint,” to Iesaka and USPatent Application No. 2003/0229398 “Prosthetic Joint,” to Iesaka, whichare each incorporated herein by reference). The femoral component of theartificial joint is fabricated by processes of investment casting andmilling. For example, a solid model comprised of a thermally labilematerial (e.g., wax) is made by injection molding and then a ceramicshell is created by coating the solid wax model. The ceramic shell isrecovered after melting the solid model and used as a mold to cast thefemoral component of the prosthesis. See e.g., U.S. Pat. No. 5,665,118,“Bone Prostheses with Direct Cast Macrotextured Surface Regions andMethod for Manufacturing the Same,” to LaSalle et al., which isincorporated herein by reference.

At the base of the femoral component neck and the top of the femoralcomponent stem, a row of fluid deflector structures (see e.g. FIG. 5)are attached. The fluid deflector structures are positioned and shapedin a manner predicted to deflect synovial fluids away from the interfacebetween the femur and the implanted stem, and to diffuse the fluidpressure at the interface, thus reducing the possibility ofperiprosthetic bone resorption (see e.g., Fahlgren et al., “FluidPressure and Flow as a Cause of Bone Resorption,” Acta Orthopaedica 81:508-516, 2010 which is incorporated herein by reference). The fluiddeflector structures are fabricated from polyethylene and include a bandlinking an edge of each of a series of the fluid deflector structures ata set orientation relative to the circumference of the band. The base ofthe femoral component neck and the top of the femoral component stem aremachined to include small surface grooves positioned to stabilize thefluid deflection structures. Each groove corresponds to the size andshape of the band linking a series of the fluid deflector structures(see, e.g. FIG. 6).

Fluid deflector structures are created from polyethylene in suitableshapes and sizes to line the border between the titanium stem and thefemur and configured to deflect synovial fluid away from the stem-boneinterface in vivo. Compression molding is used to form the polymericfluid deflector structures directly onto the metallic stem at the siteof the groove. See e.g., U.S. Pat. No. 5,879,404, “Acetabular Cups andMethods of their Manufacture,” issued to Bateman et al. and U.S. Pat.No. 6,368,354, “Acetabular Bearing Assembly for Total Hip Joints,”issued to Burstein, which are each incorporated herein by reference.Fluid deflector structures approximately 1 cm long and 0.5 cm in widthare cast to protrude around the circumference of the femoral stem in aconfiguration predicted to divert synovial fluid away from the bone-steminterface and to reduce the transient synovial fluid pressure duringphysiological use of the joint. The fluid deflector structures areflexible, but firm enough to remain extended above the surface of theprosthesis and positioned to guide synovial fluid flow away from thestem-bone interface in vivo. See FIGS. 2 and 4. For example, a model hipjoint subjected to axial and torsional forces displays high and lowpressure in the proximal posterior and proximal anterior areasrespectively of the femoral stem (see e.g., Bartlett et al., “In VitroInfluence of Stem Surface Finish and Mantle Conformity on PressureGeneration in Cemented Hip Arthroplasty,” Acta Orthopaedica 80: 139-143,2009 which is incorporated herein by reference). Fluid pressuredifferentials drive high estimated synovial fluid flow rates (e.g., 20mm/s) and promote osteolysis that is observed in vivo in animal modelsof bone resorption (see e.g., Fahlgren et al., ibid., which isincorporated herein by reference). Fluid deflector structures areconstructed to occlude the interface between the prosthesis stem andfemoral bone and to reduce the transient pressure and divert the flow ofjoint fluid during physiological movement (see FIGS. 2 and 4).

The acetabular component of the artificial joint is constructed using aprocess of investment casting that employs titanium in the outer cup andtitanium and polyethylene in the inner cup (see e.g., U.S. Pat. No.5,665,118 ibid. which is incorporated herein by reference). During thecasing process, fluid deflector structures are constructed frompolyethylene and integrally formed at the margin of the outer cup. Thesefluid deflection structures are fabricated of a size and shape expectedto divert synovial fluid away from the interface between the pelvic boneand the outer cup during in vivo use. See, e.g. FIGS. 1-4. Manufactureof acetabular cups with titanium and polyethylene components isdescribed (see e.g., U.S. Pat. No. 5,879,404, ibid. which isincorporated herein by reference).

If desired, a hip joint prosthesis can be surgically implanted thatincludes both a femoral component with fluid deflection structuresattached and an acetabular cup with fluid deflection structuresattached, as described above. A medical caregiver can also select a hipjoint prosthesis that has fluid deflection structures attached to eitherthe femoral component or the acetabular component. In this situation,the corresponding components without fluid deflection structures can beobtained for implantation in conjunction with the component with fluiddeflection structures attached. For example, a femoral component with atitanium stem and a cobalt chromium alloy head is available from StrykerOrthopaedics, Mahwah, N.J. A acetabular component with a titanium shelland polyethylene bearings is available from Stryker Orthopaedics,Mahwah, N.J.

Example 2 An Artificial Knee Joint Including Fluid Deflector Structuresand an Encapsulation/Filtration Membrane Configured to RetainParticulates

A knee joint prosthesis is fabricated with fluid deflector structures onselect non-contact surfaces of the device. The fluid deflectorstructures are of a size, shape and position expected to divert jointfluids away from the interfaces of the device and the patient's bone,thereby reducing the likelihood of aseptic loosening of the prostheticimplant. The knee joint prosthesis is fabricated including a filtermembrane configured to capture debris particles arising in the jointthat can be present in the joint fluid. The fluid deflector structuresare configured to divert fluid flow through the filter, promotingremoval of debris particles from the joint fluid. Polyethylene and metaldebris particles in joint fluid, for example, are generally associatedwith osteolysis and loosening of artificial knee implants (see e.g.,Collier et al., “Osteolysis After Total Knee Arthroplasty: Influence ofTibial Baseplate Surface Finish and Sterilization of PolyethyleneInsert, Findings at Five to Ten Years Postoperatively,” J. Bone JointSurg. 87-A: 2702-2708, 2005 which is incorporated herein by reference).

The knee joint prosthesis comprises a femoral component and a tibialpart including a tibial spacer, and a tibial tray component. The tibialspacer is fabricated from polyethylene. See e.g., U.S. PatentApplication No. 2005/0055101 to Sifneos, “Endoprosthesis of the Kneeand/or Other Joints,” which is incorporated herein by reference. Forexample, total knee replacement prostheses are commonly availableincluding polyethylene components. See, e.g., Xie, “A Systematic Reviewon Performance of the Vanguard® Complete Knee System,” Form No.BOI0500.0, REV083111, dated Jun. 30, 2011 and available from BiometInc., Warsaw, Ind., which is incorporated herein by reference. Othercomponents are metallic, preferably fabricated from titanium.

Fluid deflector structures are created from polyethylene and attached tothe knee prosthesis at non-contact surfaces of the prosthesiscomponents. The fluid deflector structures are of a size and shapeexpected to deflect synovial fluid away from the prosthesis-boneinterface. Compression molding methods are used to form the polymericfluid deflector structures directly onto the metallic femoral componentand tibial tray component (see e.g., U.S. Pat. No. 5,879,404, ibid. andU.S. Pat. No. 6,368,354, ibid, which are each incorporated by referenceherein). Fluid deflector structures approximately 1 cm long and 0.5 cmin width are molded to protrude over the boundary of the femoralcomponent and around the circumference of the tibial tray component. SeeFIGS. 8 and 9.

At the margin of the femoral component adjacent to the prosthesis-boneinterface a row of fluid deflector structures (see FIGS. 8 and 9)fabricated from polyethylene. The fluid deflector structures areconfigured to deflect synovial fluids away from the interface betweenthe femur and the implanted femoral component, and to reduce thevelocity of fluid flow in the joint, thus reducing periprosthetic boneresorption (see e.g., Fahlgren et al., ibid., which is incorporatedherein by reference). A row of polyethylene fluid deflector structuresis also attached to one or more of the tibial components and configuredto divert and impede fluid flows away from the interface between thetibial component and bone (see FIGS. 8 and 9).

The tibial tray component of the artificial joint is constructed using aprocess of investment casting (see e.g., U.S. Pat. No. 5,665,118 ibid.,which is incorporated by reference herein) that employs titanium alloys.Fluid deflector structures constructed from polyethylene are formed onthe margin of the tibial tray component to prevent synovial fluid fromentering the interface between the tibial tray baseplate and the tibia.See FIGS. 8-9 and Xie, ibid, which is incorporated by reference herein.Manufacture of prostheses with titanium and polyethylene components isas described (see e.g., U.S. Pat. No. 5,879,404, ibid, which isincorporated by reference herein).

The fluid deflector structures are flexible but firm enough to remainextended above the surface of the prosthesis and positioned to guidesynovial fluid flow from transient regions of high fluid pressure totransient regions of low fluid pressure. For example, a model jointsubjected to physiological axial and torsional forces displaysrelatively high and low pressure in the proximal posterior and proximalanterior areas respectively of a femoral stem (see e.g., Bartlett etal., 2009, ibid., which is incorporated by reference herein). Fluidpressure differentials result in high estimated fluid flow rates (e.g.,20 mm/s) which are associated with osteolysis and bone resorption (seee.g., Fahlgren et al., ibid., which is incorporated by referenceherein). Fluid deflector structures are configured and attached so as toocclude the interface of the femoral component and bone where theydivert and diffuse the flow of joint fluid (see FIG. 9). Fluid deflectorstructures are also of a size, shape and position to direct joint fluidflow toward a filter in the artificial joint. The combination of jointfluid flow diversion away from the bone-implant interface and toward afilter have synergetic effects to reduce the possible occurrence ofosteolysis and implant loosening.

To remove debris particles in the joint, a membrane filter is fabricatedto surround the artificial knee joint and trap particles present in thesynovial joint fluid. Particles can, for example, arise from wear on thepolyethylene or metal components of the joint. Particles can, forexample, arise from debris remaining after the implantation surgery.Particulate debris arising from the articulating surfaces or elsewherein the artificial joint are trapped by a membrane surrounding the jointcomponents. The membrane surrounding the joint components is configuredto trap debris particles while allowing joint fluid to pass through. Amembrane filter comprised of silicone, hydroxyl-ethyl-methacrylate andpolyvinylpirrolidone is fabricated to filter and trap particulates whichmay arise in the artificial joint (see U.S. Patent Application No.2005/0055101, ibid., which is incorporated by reference herein). Amembrane filter is constructed as a tube which attaches at one end tothe bone adjacent to the tibial tray-tibia bone interface, while thedistal end of the tube attaches to the femoral bone adjacent to thefemoral component interface. Membrane filters are composed of laminatesof polytetrafluoroethylene (PTFE) of different fibril lengths to trapparticles less than 0.2 microns in diameter while allowing fluids topass. See e.g.: U.S. Pat. No. 6,132,470, “Apparatus and Method forProtecting Prosthetic Joint Assembly from Wear,” to Berman; U.S. Pat.No. 5,879,406 “Artificial Joint Bioprosthesis for Mitigation of Wear,”to Lilley; U.S. Pat. No. 6,432,141 “Joint Prosthesis Assembly and Methodfor Installing Same,” to Stocks; US Patent Application No. 2003/0130740“Joint Prosthesis Assembly and Method for Installing Same,” to Stocks;U.S. Pat. No. 7,144,427 “Apparatus and Method for Advancing SynovialFluid in a Prosthetic Joint,” to Southworth; US Patent Application No.2004/0111162 “Apparatus and Method for Advancing Synovial Fluid in aProsthetic Joint,” to Southworth; US Patent Application No. 2005/0055101“Endoprosthesis of the Knee and/or other Joints,” to Sifneos; and U.S.Pat. No. 5,571,195 “Prosthesis for an Artificial Joint Having WearParticle Collection Capability,” to Johnson, which are each incorporatedherein by reference. Methods to attach a membrane filter to the boneadjacent to an artificial joint are described (see e.g.: U.S. PatentApplication No. 2005/0055101, ibid.; U.S. Pat. No. 4,731,088, “EnclosureMember for Prosthetic Joint” to Collier; and U.S. Pat. No. 6,132,470,ibid., which are each incorporated by reference herein). The membranefilter can, in some embodiments, include one or more stay rings tominimize the possibility of mechanical entrapment of the membranefilter. See U.S. Pat. No. 5,514,182 “Prosthetic Joint with SemipermeableCapsule with Reinforcing Ribs,” to Shea, which is incorporated herein byreference.

Example 3 An Artificial Hip Joint Including Actuated Fluid DeflectorStructures Configured to Divert Synovial Fluid and Associated DebrisParticles Away from Prosthesis-Bone Interface

An artificial hip joint prosthesis is fabricated with actuated fluiddeflector structures attached to select non-contact surfaces of thedevice. The fluid deflector structures are configured to divert jointfluid and associated debris particles away from interfaces between theartificial joint and the patient's bones and to reduce the transientfluid pressure at the interfaces during physiological use of the joint.The altered fluid flow is configured to reduce the likelihood ofosteolysis and aseptic loosening of the prosthetic implant.

The hip joint prosthesis includes a femoral component which includes ahead (or ball), a neck and a stem which is implanted in the medullarycanal of the femur. There is also an acetabular component that includesan outer and inner cup with the outer cup attached to pelvic bone andthe inner cup forming a socket bearing the head of the femoralcomponent. The neck and stem of the femoral component are fabricatedfrom titanium (see e.g., U.S. Pat. No. 6,761,741, ibid., which isincorporated herein by reference). Actuated fluid deflector structuresare attached to non-contact surfaces on the edge regions of the femoralcomponent and the acetabular component. The fluid deflector structuresare configured to deflect synovial fluids and debris particles away fromthe interfaces between the prosthesis components and bone, and tomitigate the pressure of fluid flow on the prosthesis-bone interfaces,thus reducing the likelihood of periprosthetic bone resorption andartificial joint loosening (see e.g., Fahlgren et al., et al., ibid.,which is incorporated herein by reference).

The artificial joint is fabricated using processes of investment castingand milling. For example, a solid model comprised of a thermally labilematerial (e.g., wax) is made by injection molding and then a ceramicshell is created by coating the solid wax model. The ceramic shell isrecovered after melting the solid model and used as a mold to cast thecomponents of the prosthesis. See e.g., U.S. Pat. No. 5,665, ibid.,which is incorporated herein by reference. A groove is milled around thecircumference of the femoral component at the base of the neck tostabilize attached actuated fluid deflector structures. A groove is alsomilled around the circumference of the acetabular component in the outercup to stabilize attached actuated fluid deflector structures.

Actuated fluid deflector structures are constructed frompolydimethylsiloxane (PDMS, available from Dow Corning Corp., Midland,Mich.) containing permanently magnetic nanoparticles. Carbon coated ironparticles approximately 70 nm in diameter (available from M K ImpexCorp., Missisauga, ON, Canada) are dispersed in PDMS and spin cast toobtain fluid deflector structures approximately 1 cm long and 3 mm wide.See e.g., Willem van Engen, Master's Thesis: “Artificial cilia formicrofluidics exploring the use of a horizontally microstructuredferromagnetic PDMS composite,” Eindhoven University of Technology, 2008,Eindhoven, Netherlands, which is incorporated herein by reference. Thefluid deflector structures are magnetized by repeated movement of apermanent magnet with a magnetic field of about 500 mTesla along thelong axis of the fluid deflector structures. The fluid deflectorstructures are attached to a polymeric band by adhesion and the bands,containing approximately 2 fluid deflector structures per centimeter,are inserted in the grooves of the femoral and acetabular components.

Magnetic fluid deflector structures approximately 1 cm long and 3 mm inwidth are positioned around the circumference of the femoral stem andthe acetabular cup in positions predicted to divert synovial fluid awayfrom the bone-stem interface and to mitigate transient high pressure inthe joint fluid due to physiological movement of the joint. The fluiddeflector structures are flexible but firm enough to remain extendedabove the surface of the prosthesis and positioned to guide synovialfluid flow. For example, a model hip joint subjected to axial andtorsional forces displays high and low pressure in the proximalposterior and proximal anterior areas respectively of the femoral stem(see e.g., Bartlett et al., 2009, ibid., which is incorporated herein byreference). Fluid pressure differentials and high estimated fluid flowrates (e.g., 20 mm/s) promote osteolysis and bone resorption (see e.g.,Fahlgren et al., ibid., which is incorporated herein by reference).Magnetic fluid deflector structures are configured to mitigate fluidflow and pressure at the interface of the prosthesis and bone in vivo.The magnetic fluid deflector structures can be fabricated frompolyethylene including magnetic nanoparticles. See: Chatterjee et al.,“Synthesis of Polyethylene Magnetic Nanoparticles,” European Cells andMaterials 3(2): 98-101 (2002); Wang et al., “Novel Magnetic PolyethyleneNanocomposites Produced by Supported Nanometer Magnetic Ziegler-NattaCatalyst,” Polymer International 49: 184-188 (2000); Millan et al.,“Magnetic Polymer Nanocomposites,” chapter 17 in Polymer Nanocomposites,Mai and Yu, eds. CRC Press, 2006; and Killeya, “First Plastic MagnetsCreated,” New Scientist (30 Aug. 2004), which are each incorporatedherein by reference.

A permanent magnet is constructed within the femoral component andconfigured to actuate the magnetic deflectors. A permanent magnet with amagnetic field of approximately 500 mTesla is placed in the stem regionof the femoral component to form a magnetic field configured to interactwith the magnetic fluid deflector structures on the femoral andacetabular components as the hip joint moves. The permanent magnetwithin the femoral component has a size, shape and position expected tocreate a magnetic field that is roughly perpendicular to the fluiddeflector structures. For example, a magnetic field of approximately 50mTesla applied perpendicular to the magnetic deflectors causes adeflection of approximately 0.5 millimeter in an artificial cilia (seevan Engen, ibid., which is incorporated herein by reference).

Alternatively, an electromagnet can be used to actuate the fluiddeflector structures. See US Patent Application No. 2008/0306324“Magnetic Joint Implant,” to Bonutti and Beyers, which is incorporatedherein by reference. Reversing the direction of electrical current inthe electromagnet switches the magnetic field direction by 180 degreesand reverses the direction of movement of the magnetic fluid deflectorstructures. An electromagnet can be used to create a magnetic field ofapproximately 500 mTesla, increasing the deflection of the magneticfluid deflector structures by 10 fold relative to a 50 mTesla magneticfield. Moreover, rapid switching of the direction of the magnetic fieldwill result in “beating” of the magnetic fluid deflector structures toactively divert synovial fluid flow away from prosthesis-boneinterfaces. The electromagnet can be empowered by a battery orpiezoelectric elements in the artificial hip prosthesis. Piezoelectricdevices suitable to capture and store energy from the movement of anartificial joint are known (see e.g., Keawboonchuay et al., “MaximumPower Generation in a Piezoelectric Pulse Generator,” IEEE TransactionsOn Plasma Science, 31: 123-128, 2003, which is incorporated herein byreference).

Example 4 An Artificial Hip Joint Including Actuated Fluid DeflectorStructures Configured to Capture Debris Particles

A hip joint prosthesis is fabricated with actuated fluid deflectorstructures on select non-contact surfaces of the device. The actuatedfluid deflector structures are configured to divert joint fluid anddebris particles away from the interface regions between the implantedartificial joint and the patient's bones. Also the actuated fluiddeflector structures include distal edge regions with adhesive tips. Theadhesive regions of the actuated fluid deflector structures areconfigured to capture and sequester debris particles in the joint fluid.Debris particles within the joint fluid are associated with an increasedlikelihood of osteolysis and aseptic loosening of the prostheticimplant.

The hip joint prosthesis includes a femoral component which includes ahead (or ball), a neck, and a stem which is configured to be implantedin the medullary canal of the femur. The hip joint prosthesis alsoincludes an acetabular component that includes an outer and inner cup,with the outer cup configured to be attached to pelvic bone and theinner cup forming a socket that bears the head of the femoral componentin vivo. The neck and stem of the femoral component are made fromtitanium (see e.g., U.S. Pat. No. 6,761,741, ibid., which isincorporated herein by reference).

Actuated fluid deflector structures are formed at the boundaries of thefemoral component and the acetabular component. The fluid deflectorstructures are configured to deflect synovial fluid flow and associateddebris particles away from the interfaces between the prosthesiscomponents and bone and to mitigate transient joint fluid pressure onthe prosthesis-bone interfaces during physiological use of the joint.The fluid deflector structures are also configured to capture debrisparticles in the joint fluid, thus reducing the likelihood ofperiprosthetic bone resorption and artificial joint loosening (see e.g.,Fahlgren et al., ibid., which is incorporated herein by reference).

The artificial joint is fabricated using processes of investmentcasting, milling and compression molding. For example, a solid modelcomprised of a thermally labile material (e.g., wax) is made byinjection molding and then a ceramic shell is created by coating thesolid wax model. The ceramic shell is recovered after melting the solidmodel and used as a mold to cast the components of the prosthesis. Seee.g., U.S. Pat. No. 5,665,118, ibid., which is incorporated herein byreference. A series of cavities are cast around the circumference of thefemoral component and at the base of the neck of the acetabularcomponent, with associated apertures within non-contact surfaces of theprosthesis. These cavities are configured to contain actuated fluiddeflector structures with size, shape, number and position as requiredby the specific prosthesis design.

Magnetic actuated fluid deflector structures are constructed frompolydimethylsiloxane (PDMS, available from Dow Corning Corp., Midland,Mich.) containing permanently magnetic nanoparticles. Carbon coated ironparticles approximately 70 nm in diameter (available from M K ImpexCorp., Missisauga, ON, Canada) are dispersed in PDMS to form acomposite. This composite is then cast in the cavities of the femoraland acetabular components to form fluid deflector structuresapproximately 1 cm long and 3 mm wide protruding from the cavities (seee.g., van Engen, ibid., which is incorporated herein by reference). Eachfluid deflector structure includes a proximal end that is positionedwithin the associated cavity, the proximal end of a size and shape to beblocked from leaving the cavity by the size and shape of the associatedaperture. Each fluid deflector structure includes a region traversingthe aperture. Each fluid deflector structure also includes a functionalregion approximately 1 cm long and 3 mm wide external to the cavity andaperture. The fluid deflector structures are magnetized by repeatedmovement of a permanent magnet along the long axis of the deflectorswith a magnetic field of about 500 mTesla. The fluid deflectorstructures also include distal edge regions which contain adhesive tipsconfigured to capture and retain debris particles. Artificial actuatedcilia which adhere to particles and are used for propelling particles(antifouling) and trapping particles (filtration) are described (seee.g., Bhattacharya et al., “Propulsion and Trapping of Microparticles byActive Cilia Arrays,” Langmuir 28: 3217-3226, (2012) which isincorporated herein by reference).

A permanent magnet is constructed in the neck of the femoral componentto actuate the magnetic fluid deflector structures with a magnetic fieldthat is oriented substantially perpendicular to the deflectors. Apermanent magnet with a magnetic field of approximately 500 mTesla isplaced in the neck region of the femoral component to actuate themagnetic fluid deflector structures on the femoral and acetabularcomponents as the hip joint moves. For example, a magnetic field ofapproximately 50 mTesla applied perpendicular to magnetic cilia has beenshown to cause a deflection of approximately 0.5 millimeter (see vanEngen, ibid., which is incorporated herein by reference). See also USPatent Application No. 2006/0149386, “Joint Prosthesis,” to Clarke andLee, which is incorporated by reference herein.

Magnetic fluid deflector structures with distal edge regions thatcontain adhesive tips are positioned around the circumference of thefemoral stem and the acetabular cup. The position, size, shape, numberand orientation of the fluid deflector structures on each prosthesiscomponent is configured to divert synovial joint fluid and associateddebris particles away from the bone-prosthesis interfaces. Each of thefluid deflector structures is also configured to trap debris particlesfrom synovial joint fluid with the adhesive tips attached to the distaledge regions of the fluid deflector structures. Models to calculate theoptimal adhesive force and stiffness for the fluid deflector structuresto trap particles are described (see Bhattacharya et al., ibid., whichis incorporated herein by reference). Actuated magnetic fluid deflectorstructures with distal edge regions that contain adhesive tips areconfigured to move in response to the motion of a magnet positionedwithin the femoral component. Physiological movement of the artificialhip joint moves the magnet within the femoral stem into proximity of thefluid deflector structures and causes the fluid deflector structures tobend or flex in response to the magnetic field. Movement of the fluiddeflector structures promotes directed fluid flow and trapping of debrisparticles (see e.g., van Engen, ibid. and Bhattacharya et al., ibid.,which are each incorporated herein by reference). Repeated “beating” ofthe fluid deflector structures during regular activities, e.g., walking,running, sitting, reclining, or sleeping, acts to divert the flow ofsynovial fluid away from the prosthesis-bone interfaces and traps debrisparticles within the fluid with the adhesive tips at the distal edgeregions of the fluid deflector structures. Thus, the artificial hipjoint with actuated adhesive fluid deflector structures reduces thelikelihood of osteolysis, periprosthetic bone resorption and prosthesisloosening in vivo.

All of the above U.S. patents, U.S. patent application publications,U.S. patent applications, foreign patents, foreign patent applicationsand non-patent publications referred to in this specification and/orlisted in any Application Data Sheet, are incorporated herein byreference, to the extent not inconsistent herewith.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

What is claimed is:
 1. An artificial joint prosthesis, comprising: abone-facing surface of an artificial joint prosthesis, the bone-facingsurface configured to face a bone-prosthesis interface in vivo; anon-load bearing surface of the artificial joint prosthesis, thenon-load bearing surface adjacent to the bone-facing surface of theartificial joint prosthesis; at least one fluid deflection structureattached to the non-load bearing surface, the at least one fluiddeflection structure including at least one flange structure positionedto extend from the non-load bearing surface, the at least one flangestructure including a first end connected to the non-load bearingsurface and a second end distal to the non-load bearing surface, whereinthe at least one flange structure is widest at the first end andnarrowest at the second end, the fluid deflection structure positionedto direct a flow of synovial fluid away from the bone-prosthesisinterface in vivo during physiological movement of the artificial jointprosthesis; and at least one particle retaining structure positioned tocontact the directed flow of synovial fluid and configured to retainnon-physiological particles present within the synovial fluid.
 2. Anartificial joint prosthesis, comprising: a bone-facing surface of anartificial joint prosthesis, the bone-facing surface configured to facea bone-prosthesis interface in vivo; a non-contact surface of theartificial joint prosthesis, the non-contact surface adjacent to thebone-facing surface of the artificial joint prosthesis; at least onefluid deflection structure attached to the non-contact surface, the atleast one fluid deflection structure including at least one flangestructure positioned to extend from the non-contact surface, the atleast one flange structure including a first end connected to thenon-contact surface and a second end distal to the non-contact surface,wherein the at least one flange structure is widest at the first end andnarrowest at the second end, the fluid deflection structure positionedto direct a flow of synovial fluid away from the bone-prosthesisinterface in vivo; and at least one particle retaining structurepositioned to contact the directed flow of synovial fluid and configuredto retain particles present within the synovial fluid.
 3. The artificialjoint prosthesis of claim 2, wherein the at least one particle retainingstructure comprises: a mesh-like structure.
 4. The artificial jointprosthesis of claim 2, wherein the at least one particle retainingstructure comprises: a filter structure.
 5. The artificial jointprosthesis of claim 2, wherein the at least one particle retainingstructure comprises: a foam structure.
 6. The artificial jointprosthesis of claim 2, wherein the at least one particle retainingstructure comprises: a group of projections, each of the projectionspositioned to contact the flow of synovial fluid and configured toretain particles present within the synovial fluid.
 7. The artificialjoint prosthesis of claim 2, wherein the at least one particle retainingstructure comprises: a hydrophobic surface.
 8. The artificial jointprosthesis of claim 2, wherein the at least one particle retainingstructure comprises: at least one antibody affixed to a surface of theparticle retaining structure.
 9. The artificial joint prosthesis ofclaim 2, wherein the at least one particle retaining structure isaffixed to a plurality of surfaces of the artificial joint prosthesis.10. The artificial joint prosthesis of claim 2, comprising: at least twocomponents, a first component which includes at least one fluiddeflection structure affixed to a non-contact surface, and a secondcomponent which includes at least one particle retaining structureaffixed to a non-contact surface.
 11. A hip joint prosthesis,comprising: a bone-facing surface of a hip joint prosthesis, thebone-facing surface configured to face a bone-prosthesis interface invivo; a non-contact surface of the hip joint prosthesis, the non-contactsurface adjacent to the bone-facing surface of the hip joint prosthesis;at least one fluid deflection structure attached to the non-contactsurface, the at least one fluid deflection structure including at leastone flange structure positioned to extend from the non-contact surface,the at least one flange structure including a first end connected to thenon-contact surface and a second end distal to the non-contact surface,wherein the at least one flange structure is widest at the first end andnarrowest at the second end, the fluid deflection structure positionedto direct a flow of synovial fluid away from the bone-prosthesisinterface in vivo; and at least one particle retaining structurepositioned to contact the directed flow of synovial fluid and configuredto retain particles present within the synovial fluid.
 12. The hip jointprosthesis of claim 11, wherein the at least one particle retainingstructure comprises: a mesh-like structure.
 13. The hip joint prosthesisof claim 11, wherein the at least one particle retaining structurecomprises: a filter structure.
 14. The hip joint prosthesis of claim 11,wherein the at least one particle retaining structure comprises: a foamstructure.
 15. The hip joint prosthesis of claim 11, wherein the atleast one particle retaining structure comprises: a group ofprojections, each of the projections positioned to contact the flow ofsynovial fluid and configured to retain particles present within thesynovial fluid.
 16. The hip joint prosthesis of claim 11, wherein the atleast one particle retaining structure comprises: a hydrophobic surface.17. The hip joint prosthesis of claim 11, wherein the at least oneparticle retaining structure comprises: at least one antibody affixed toa surface of the particle retaining structure.
 18. The hip jointprosthesis of claim 11, wherein the at least one particle retainingstructure comprises: a structure configured to retain non-physiologicalparticles present in the synovial fluid.
 19. The hip joint prosthesis ofclaim 11, wherein the at least one particle retaining structure isaffixed to a plurality of surfaces of the hip joint prosthesis.
 20. Thehip joint prosthesis of claim 11, comprising: at least two components, afirst component which includes at least one fluid deflection structureaffixed to a non-contact surface, and a second component which includesat least one particle retaining structure affixed to a surface.
 21. Aknee joint prosthesis, comprising: a bone-facing surface of a knee jointprosthesis, the bone-facing surface configured to face a bone-prosthesisinterface in vivo; a non-contact surface of the knee joint prosthesis,the non-contact surface adjacent to the bone-facing surface of the kneejoint prosthesis; at least one fluid deflection structure attached tothe non-contact surface, the at least one fluid deflection structureincluding at least one flange structure positioned to extend from thenon-contact surface, the at least one flange structure including a firstend connected to the non-contact surface and a second end distal to thenon-contact surface, wherein the at least one flange structure is widestat the first end and narrowest at the second end, the fluid deflectionstructure positioned to direct a flow of synovial fluid away from thebone-prosthesis interface in vivo; and at least one particle retainingstructure positioned to contact the directed flow of synovial fluid andconfigured to retain particles present within the synovial fluid. 22.The knee joint prosthesis of claim 21, wherein the at least one particleretaining structure comprises: a mesh-like structure.
 23. The knee jointprosthesis of claim 21, wherein the at least one particle retainingstructure comprises: a filter structure.
 24. The knee joint prosthesisof claim 21, wherein the at least one particle retaining structurecomprises: a foam structure.
 25. The knee joint prosthesis of claim 21,wherein the at least one particle retaining structure comprises: a groupof projections, each of the projections positioned to contact the flowof synovial fluid and configured to retain particles present within thesynovial fluid.
 26. The knee joint prosthesis of claim 21, wherein theat least one particle retaining structure comprises: a hydrophobicsurface.
 27. The knee joint prosthesis of claim 21, wherein the at leastone particle retaining structure comprises: at least one antibodyaffixed to a surface of the particle retaining structure.
 28. The kneejoint prosthesis of claim 21, wherein the at least one particleretaining structure comprises: a structure configured to retainnon-physiological particles present in the synovial fluid.
 29. The kneejoint prosthesis of claim 21, wherein the at least one particleretaining structure is affixed to a plurality of surfaces of the kneejoint prosthesis.
 30. The knee joint prosthesis of claim 21, comprising:at least two components, a first component which includes at least onefluid deflection structure affixed to a non-contact surface, and asecond component which includes at least one particle retainingstructure affixed to a non-contact surface.
 31. A shoulder jointprosthesis, comprising: a bone-facing surface of a shoulder jointprosthesis, the bone-facing surface configured to face a bone-prosthesisinterface in vivo; a non-contact surface of the shoulder jointprosthesis, the non-contact surface adjacent to the bone-facing surfaceof the shoulder joint prosthesis; at least one fluid deflectionstructure attached to the non-contact surface, the at least one fluiddeflection structure including at least one flange structure positionedto extend from the non-contact surface, the at least one flangestructure including a first end connected to the non-contact surface anda second end distal to the non-contact surface, wherein the at least oneflange structure is widest at the first end and narrowest at the secondend, the fluid deflection structure positioned to direct a flow ofsynovial fluid away from the bone-prosthesis interface in vivo; and atleast one particle retaining structure positioned to contact thedirected flow of synovial fluid and configured to retain particlespresent within the synovial fluid.
 32. The shoulder joint prosthesis ofclaim 31, wherein the at least one particle retaining structurecomprises: a mesh-like structure.
 33. The shoulder joint prosthesis ofclaim 31, wherein the at least one particle retaining structurecomprises: a filter structure.
 34. The shoulder joint prosthesis ofclaim 31, wherein the at least one particle retaining structurecomprises: a foam structure.
 35. The shoulder joint prosthesis of claim31, wherein the at least one particle retaining structure comprises: agroup of projections, each of the projections positioned to contact theflow of synovial fluid and configured to retain particles present withinthe synovial fluid.
 36. The shoulder joint prosthesis of claim 31,wherein the at least one particle retaining structure comprises: ahydrophobic surface.
 37. The shoulder joint prosthesis of claim 31,wherein the at least one particle retaining structure comprises: atleast one antibody affixed to a surface of the particle retainingstructure.
 38. The shoulder joint prosthesis of claim 31, wherein the atleast one particle retaining structure is affixed to a plurality ofsurfaces of the shoulder joint prosthesis.
 39. The shoulder jointprosthesis of claim 31, comprising: at least two components, a firstcomponent which includes at least one fluid deflection structure affixedto a non-contact surface, and a second component which includes at leastone particle retaining structure affixed to a non-contact surface.